Why does the Garuda Purana say that the Mahabharata has been undergoing interpolations since Satya yuga?

Question

In the Garuda Purāna, we come across the following verse-

दैत्याः सर्व विप्रकुलेषु भूत्वा कृते युगे भारते षट्सहस्र्याम् । निष्कास्य कांश्चिन्नवनिर्मितानां निवेशनं तत्र कुर्वन्ति नित्यम् ॥ ३,१.६९ ॥

In Bharatavarsa, in the golden age (satyayuga) the daityas are born in the brahmin families. They take some Verses out of the Bharata (Mahabharata) consisting of 6000 verses and replace them by new ones.

~ Garuda Purana Brahma Khanda Chapter 1

But the Mahabharata itself was compiled in the Dvāparayuga, so how is it possible for it to undergo interpolations since the Satya Yuga?

Answer 1

I cannot find any term in Shloka pointing that the term “युगे” means Satyayug. See context of whole chapter, rather then picking a Shloka, it is clear that the chapter is discussing about Kaliyuga.

For context you can see Shloka 43 which is talking about the important Puranas of Kaliyuga.