Okay, YouTube must have made more un-necessary changes to the site, because we clearly have some new bugs and glitches that are super annoying...
First of all, the subscriptions module is acting up again, only this time, videos are actually disappearing, so I guess at this point, the old glitch where videos you've already viewed resurfacing in the subscriptions module weeks or even months after you've already watch them is a GOOD thing now, since sometimes, you'll see a video that actually never appeared in your subscriptions when they were first uploaded.
The video player itself has been acting up for like a month now with all kinds of peculiarities, likes sometimes the videos won't buffer, yet you can still watch them; or like today (and other occasions) where you're watching a video, and for some reason, at any given moment, the video will automatically restart (and sometimes multiple times).