Yeah, Blender made a last minute API change that ends up throwing an exception. If your 2.80 is too new, you are screwed for the short term, see https://forum.babylonjs.com/t/do-not-refresh-with-a-new-version-of-blender-2-80-yet/3421/3
I have already fixed this, but I have a number of changes for the next version already started, so 6.0 will never be patched, sorry.
While the file could be big, could you post the file .babylon file somewhere, which has the problem only in 4.0? No textures should be needed to see the problem.