I don't think you're right. I took another video, this time from an earlier time mark, and you can see that the same problem happens when the creature lowers its head as well. I really don't think this can be attributed to just angles. It looks like it's moving across the head. (youtube's compression makes it harder to see than I'd like, so to see for yourself, the timestamp is 43:50 If you look closely, you can see the texture sliding.)
https://youtu.be/ndx-3VGsuIc