I dont know how to explain this, help!

its like there’s a part or something there that makes me walk on it, but I’ve checked there’s nothing there

Are there any unions/meshes near it?
or select all part in workspace and see if there’s any selection box that comes over it

that whole square is union, I cut out the inside of the rectangle as well as circular doors

separate it
try to use less unions because sometimes they generate bad collision box
You can use 4 parts to make a room like that and a part cut out by cylinder for the door

It’s just a union bug. Happens to me all the time.