Hi! Thanks for your comment and sorry for late reply.
Based on the info you've provided I can tell that the UV mapping is wrong, however, it is expected as a new mesh was generated with default UV layout for that whole mesh (my assumption).
There are a few options worth trying:
1. Use "UV Unwrap" node to get proper UV mapping. I don't use it with my project, however, I saw some decent results in others works.
2. Similar to what is happening in Blender with this project, you may build procedural materials that will automatically wrap textures around the faces of mesh. E.g. in Blender, I sometimes use Box projection in the texture.
3. In case one of the above worked for you, you may also try baking textures to a new UV map. However, taking into account the size of meshes, it may be difficult.
Hope any of my comment helped.