Thank you very much for solving this problem. This decision helped me a lot.
I imported my model, which had a UDIM unwrap of 10 tiles, in two rows of 5 pieces, and the extreme two tiles - 1005 and 1015 shifted significantly to the side, which looked disgusting on the model, thanks to you I solved this problem.
I want to note that it is very strange that the engine does not initially use the most accurate UV for the main model, which I did for it in 3Ds Max, it turns out that other models may have problems with the scan, but they are less noticeable. To be honest, I first encountered this when working with a UDIM unwrapping with a large number of tiles.