Not heard of anyone else complaining of this and I have not seen it on my pc so Im gonna stick my neck out and say
HAR HAR HAR .....
Only kidding, it sounds like you have some instability there. That could be hard to debug or isolate. I cant think what could cause that, some memory allocation conflict but I dont know enuf about memory management in windows these days.
its not only me, i heard several people complain by now. Its not only alt tabbing. its also a lot of host time outs and so on. Maybe the server still is bugged or something after the latest crash?