First step for weird behaviour with a specific site is to clear its cookies.
It is possible to clear individual cookies but unless you can't stand to lose saved passwords it is probably best just to clear them all out. I am not an expert on cookies but I assume that it may not be straightforward to identify all the relevant ones in any case although I have successfully done it a few times and the names were as expected.
One way to easily test is to use a Private Window (google calls it Incognito Mode in chrome) which by definition has no stored cookies when you open it. Or use a different browser which will not have the corrupted cookies.