Sorry you're having this issue!
Good job. That would have been my first suggestion... especially to clear your cache!
Hmm... that shouldn't have any impact.
Ok, good to hear. If it happens again, leave BYC, clear your cache, and see if that works. If not, you may need to delete your cookie for BYC that keeps you logged in.
Oh, and make sure you don't have any addons, extensions, etc. that might be interfering.
If it persists, try another browser and/or computer/device. We'er not getting any other reports, so if it continues, I think it might be isolated to your device, browser, etc.