Yes there are instances where sruti seems to contradict. In his Introduction to Brahma Sutras According to Sri Sankara (available here - http://www.wisdomlib.org/hinduism/book/brahma-sutras/d/doc62756.html) Swami Vireswarananda writes (p v.):
The Upanishads do not contain any ready-made consistent system of thought. At first sight they seem to be full of contradictions. Hence arose the necessity of systematizing the thought of the Upanishads. Bâdârayana, to whom the authorship of the Brahma-Sutras or Vedânta-Sutras is ascribed, is not the only one who had tried to systematize the philosophy of the Upanishads. From the Brahma-Sutras itself we find that there were other schools of Vedânta which had their own following. We find the names of Audulomi, Kâsakristna, Bâdari, Jaimini, Kârshnâjini, Âsmarathya and others mentioned. All this shows that Bâdarâyana’s Sutras do not constitute the only systematic work in the Vedânta school, though probably the last and best. All the sects of India now hold this work to be the great authority and every new sect starts with a fresh commentary on it —without which no sect can be founded in this country.
Further into the Brahma Sutras, there are examples of conflict between Sruti texts. An example is found in Brahma Sutras 1.4.14-15. The verses with Sankara's commentary:
14. (Although) as regards (things created, like) ether and so on (the Vedânta texts differ), (yet there is no such conflict with respect to Brahman) as the First Cause, (on account of Its) being represented (in other texts) as taught (in one text).
The Sânkhyas contend that though the Pradhâna cannot be the First Cause according to the Sruti, yet Brahman also cannot be taken to be the First Cause taught by the Sruti. Why? Because there is conflict as regards the order of creation; for some texts say that it is Âkâsa that was first produced from Brahman, some say that it is Prâna, others that it is fire. This Sutra says that though there are conflicting views with respect to things created, that is, as regards the order of creation, yet since it is not the main object of the Sruti to teach about creation, it matters little. The main object in these descriptions is to teach that Brahman is the First Cause, and with respect to this there is no conflict; for every Vedânta text holds that Brahman is that.
15. On account of the connection (with passage referring to Brahman, nonexistence does not mean absolute nonexistence).
A further objection is raised that even as regards the First Cause there is a conflict, for some texts say that the Self created these worlds (Ait. Ar. 2. 4. 1. 2-3), others say that creation originated from non-existence (Taitt. 2. 7). Again existence is taught as the First Cause in some texts (Chh. 6. 2. 1-2). Spontaneous creation also is taught by some texts (Brih, 1. 4. 7). On account of these conflicting texts it cannot be said that all the Vedânta texts refer to Brahman uniformly as the First Cause. These objections are answered as follows: “This was: indeed non-existence in the beginning” (Taitt. 2. 7). Non-existence here does not mean absolute nonexistence but undifferentiated existence. Existence was at the beginning undifferentiated into name and form. In the texts of the Taittiriyâ Upanishad Brahman is definitely described as not being nonexistence. “He who knows Brahman as nonexisting becomes himself non-existing. He who knows Brahman as existing is known by sages as existing” (Taitt. 2 . 6). This Brahman is again described as having wished to be many and created this world. Again “How can that which is be created from non-existence?” (Chh. 6. 2. 2) clearly denies such a possibility. “Now this was then undifferentiated” (Brih. 1 . 4. 7), does not speak of spontaneous creation without a ruler, for it is connected with another passage where it is said, “He has entered here to the very tips of the finger-nails” (Brih. 1 . 4. 7), where ‘He’ refers to this ruler, and hence we have to take that the Lord, the ruler, developed what was undeveloped. Similarly Brahman, which is described in one place as existence, is referred to in another place as being the Self of all by the word ‘Âtman’. So all texts uniformly point to Brahman as the First Cause, and there is no conflict as regards this.
As I said in my comment, there are conflicts, but most if not all of a philosophical nature. It is for this reason that sruti should be read with the guidance of one's guru and with the commentaries.
From a strict interpretation Manu Smriti is smriti. Smriti is not sruti. vedic texts refer to sruti alone - to the vedas. Smriti is written by men. Manu Smriti was written by Manu. Sruti are the revealed truths directly from God. However, in common parlance or common usage many old texts are referred to as 'vedic texts'.