Hm, yea it is quite a long standing issue. I'll see if I can still get the project to run on the latest Unity version and then fix it. If it doesn't run (which I doubt) then I'll probably make some sort of remake/remaster in the future.
Thank you! I really loved the amount of content you added into the anniversary edition and was really dissapointed to find this kind of bug! Also, I don't know if you're aware, but on the level where Hogler starts to chase us for the first time, there is a lot of doors that lead into the glitchy areas with a non-existent floor!