Ok so i found the solution for my problem but as our material is set differently IDK if it will be the same solution:
for me the issue was coming from the Height info, I used the displacement Map for texture where I didn’t have a Height map, and it was actually breaking everything, I replaced it with the AO map and all the proxy tiles are fine now. I’ll make a test with a bump map later but for now i’ll stick with the AO map ( don’t forget to Uncheck RGB )
cheers