Landscape shading wrong after upgrade4.26

our studio recently upgrade project from 4.25 to 4.26 , all landscape works fine in the 4.25 , in the material texture samples all set to Shared:Wrap for support multiple textures , so when upgraded , the shading was wrong , parts of the landscape can’t load texture anymore as you see in the picture , there is no warning info in the material, please tell me how to fix that?

https://imagez.biz/i/2020/12/22/Image-7.jpg

https://imagez.biz/i/2020/12/22/Image-8.jpg

I have same issue

Seems like we have the same problem here. We just updated from 4.25.4 to 4.26.0.