This is what could find about this sutra,
Have other saints commented on Shankara's commentary for this sutra?
I am looking for such commentaries on commentaries, I found this one, where Swami Sivananda has commented on Shankara's views in his Brahma Sutra commentary:
In BRAHMA SUTRAS by Sri Swami Sivananda, Page 32, in His commentary on Sutra I.1.12,
Thus, the Sutra establishes that Anandamaya is Brahman. But the commentator Sankara has a new orientation of outlook in this regard. The Archarya says that Anandamaya cannot be Brahman because Anandamaya is one of the five sheaths or Koshas of the individual, the other four being Annamaya (physical body), Pranamaya (vital body), Manomaya (mental body), and Vijnanamaya (intellectual body). The Anandamaya is actually the causal body which determines the functions of the other sheathes. The individual enters into the Anandamaya sheath in deep sleep and enjoys bliss there, which is the reason why this sheath is called Anandamaya (bliss-filled). A coverage of individuality cannot be regarded as Brahman. Further, if Anandamaya had been Brahman itself, the individual in deep sleep will be united with Brahman in that condition. But this does not happen since one who goes to sleep returns to ordinary waking experience. Hence the Anandamaya is not Brahman.
This is what Swami Vishweshwarananda says about that translation (which you and Swamiji already have read but anyway for other readers reproduced here below):
Sankara objects to this interpretation of the Sutras and says that Anandamaya cannot be the highest Brahman. First of all, there is no justification, for suddenly changing the interpretation of the suffix 'mayat' from modification in the case of Vijnanamaya, Pranamaya, etc. in the preceding passages to abundance in the case of Anandamaya, so as to make this word refer to Brahman. Again the very idea of preponderance or abundance of bliss suggests there is also misery in it, however slight. Such an idea with respect to Brahman is absurd. So Sankara replaces this interpretation of the Sutras, which Anandagir attributes to the Vrittikara, by another, which we have reproduced above.
here is what Dr. George Thibaut (the one whose translation is provided in vedantabase I guess) says about Shankaracharya's commentary (I have removed some of His own opinion from the quote so that it makes it bit more neutral)
Adhik. VI (12-19) raises the question whether the anandamaya, mentioned in Taittriya Upanishad II, 5, is merely a transmigrating individual soul or the highest Self. Sankara begins by explaining the Sutras on the latter supposition... gives, however, finally the preference to a different explanation according to which the Sutras teach that the anandamaya is not Brahman, since the Upanishad expressly says that Brahman is the tail or support of the anandamaya.
Reference: The Vedanta Sutras by Dr. George Thibaut.
Here is another source where Swami Nikhilananda displays knowledge of Shankara's disagreement that Anandamaya kosha is the Supreme Brahman itself (from Swami Nikhilananda’s translation of the Taittiriya):
It should be noted that the Taittiriya Upanishad itself stops its descriptions of the successive ‘selves’ with the Anandamaya kosha. There is therefore the implication that this is the ‘highest’ Self, i.e. that it is not itself a ‘covering’ of something further. This doubt is raised in the Brahma Sutra Topic 6 (Anandamayo.bhyAsAt – I.1.12 – 19). The doubt raised is that Anandamaya cannot be the paramAtman because it has the form of the body, has parts (head, tail etc) and has joy, whereas the Self is formless, partless and limitless. The sutra concludes that it is Brahman, because Ananda is repeatedly uses as an ‘indicator’ or ‘characteristic’ of Brahman. The Taittiriya concludes that ‘Ananda is Brahman’ (II.6.1) and the Brihadaranyaka says that ‘Knowledge and bliss is Brahman’ (II.9.27) so the ‘Self made of bliss’ must be Brahman also. It is the most subtle in the series of increasing levels of subtlety pointed out in the metaphor.
Shankara disagrees and states that Anandamaya is not Brahman but the last of the five sheaths. It is the ‘causal body’ for the other four. We enjoy bliss in deep sleep but we are clearly not ‘united’ with Brahman because we return to ordinary waking afterwards. Anandamaya is the fluctuating bodily enjoyment or ‘reflection of’ the real Ananda, whereas Ananda itself is Brahman.
Reference: Swami Nikhilananda’s translation of the Taittiriya.
Has Adi Shankara provided His knowledge about the Anandamaya Kosha in His other works?
Let us see what Adi Shankaracharya says in Vivekachudamani, 207
The blissful sheath (Anandamaya Kosha) is that modification of Nescience which manifests itself catching a reflection of the Atman which is Bliss Absolute; whose attributes are pleasure and the rest; and which appears in view when some object agreeable to oneself presents itself. It makes itself spontaneously felt by the fortunate during the fruition of their virtuous deeds; from which every corporeal being derives great joy without the least effort.
Also Vivekachudamani, 209
Nor is the blissful sheath the Supreme Self, because it is endowed with the changeful attributes, is a modification of the Prakriti, is the effect of past good deeds, and imbedded in the other sheaths which are modifications.
So everybody seems to be aware of the fact that Shankaracharya believed that Anandamaya kosha is not Brahman. Also everyone refers to the fact that Shankaracharya in His Brahma Sutra Bashya expressed the interpretation that Anandamaya Kosha is not Brahman. Now comes the question, where in the Sutra does Shankaracharya actually refute that Anandamaya is not Brahman?
Where in the Sutra does He actually provide His arguments against the traditional interpretation of the Sutra
It turns out that all this information is present in His commentary on Sutra 19 - I.1.19. I am not sure if it is present in the Internet link which you showed me. But in the book that I am looking at, which is
'VEDÂNTA-SUTRAS With the Commentary by SAÑKARÂCHÂRYA Translated by GEORGE THIBAUT'
it is very clear what Shankaracharya is saying:
But, in reality, the following remarks have to be made concerning the true meaning of
the word 'ânandamaya.' On what grounds, we ask, can it be maintained that the
affix 'maya' after having, in the series of compounds beginning with annamaya and
ending with vijńânamaya, denoted mere modifications, should all at once, in the word
ânandamaya, which belongs to the same series, denote abundance, so that ânandamaya
would refer to Brahman?
We therefore must conclude that the affix maya, in the word ânandamaya, does not
denote abundance, but expresses a mere effect, just as it does in the words annamaya
and the subsequent similar compounds.
And as Brahman is the cause, it cannot at the same time be called the member, in the literal sense of the word, of the Self of bliss, which is nothing but one of Brahman's effects. The other Sutras also (which refer to the Self of bliss) are to be considered, as well as they may, as conveying a knowledge of Brahman, which (Brahman) is referred to in the passage about the tail.
If it were a settled matter that Brahman is denoted by the term, 'the Self consisting of bliss,' then we could assume that in the subsequent passages, where merely the word 'bliss' is employed, the term 'consisting of bliss' is meant to be repeated; but that the Self consisting of bliss is not Brahman, we have already proved by means of the reason of joy being its head, and so on. Hence, as in another scriptural passage, viz. 'Brahman is knowledge and bliss' (Bri. Up. III, 9, 28), the mere word 'bliss' denotes Brahman, we must conclude that also in such passages as, 'If that bliss existed not in the ether,' the word bliss is used with reference to Brahman, and is not meant to repeat the term 'consisting of bliss.' The repetition of the full compound, 'consisting of bliss,' which occurs in the passage, 'He reaches that Self consisting of bliss' (Taitt. Up. II, 8), does not refer to Brahman, as it is contained in the enumeration of Non-Selfs, comprising the Self of food, &c., all of which are mere effects, and all of which are represented as things to be reached.-
This is all very heavy stuff. So let me provide what I understood from it:
He is basically saying that while the repitition of the word 'bliss' would imply that Bliss is Brahman that does not mean that the 'Self consisting of Bliss' denotes it. He is saying that the sentence 'consisting of bliss' implies that the term bliss is in this context an effect of the Self. Thus the Self is above it. If 'Self consisting of bliss' was the Highest Brahman, then the sentence 'consisting of bliss' would be repeated over scripture to denote Brahman. But that is not so, only bliss is repeated.
The entire commentary gives a detailed refutation. However, I do not want to quote everything here. The book is available on Google. All the best.