Okay, this started to happen about ten days ago. I would be playing along merrily and then my E prompt to pick something up would go dead. Hit it all you want, nothing happens. My summons (I'm a Level 50 CP 622 sorcerer) stop moving with me and hover in place, and I can't dismount or mount. I can still move freely, but after a few seconds more, I'm kicked to the sign-in screen. If I try to sign in again quickly, I will sometimes be told that I'm already signed in.
Sign in again, twenty minutes to half an hour later, the same thing happens. Regularly.
There have been some odd variations, though. Once I hit a massive slowdown when fighting a Frost Atronach. It went on for ages with him moving a bit, me moving a bit, and then I crashed out. I started up again, fully expecting to find my character dead, but somehow she killed the atronach (which had 72% of health the last time I saw it). So she must have continued delivering blows but somehow these weren't being fed through to the animation.
If the bug hit while I was in the building tool, when I tried to place something, I would click but nothing would happen; the thing I was trying to place remained stuck to my cursor. If I clicked again, I would be told that a building operation was in progress and please wait. Then I would crash.
I've checked all the usual things, reduced the graphics quality, and so on. Nothing has affected the frequency of the crash.
This is very not fun. Suggestions?