It's just as invalid to assume that it's just his device that has a problem, as it would be if he assumed that everyone's device was broken. If he applied the update and got this behaviour, then there is a problem in the update. Whether than may be local to him, and fixable in just his case, or apply to more people and require a more mature fix, is for us to establish. This is why saying 'it works for me' isn't helpful at all.

EDIT: not reproducable here. I switched my orientation to landscape and back and File Browser still operated correctly. What did you have that set to when you upgraded?