I was working on a file in 2.9. When 3.0 came out, I downloaded it and opened up the file I've been working on. I quickly found certain elements were not working so I went back to v2.9 only to find my header in 3D viewport is now overlapping. That is not the case with new files so it seems like my file is the culprit but I have no idea how to fix it.
Here are two photos of how it looks now vs how it should look below.
Any help would be much appreciated.