I've been having similar issues here recently. Sometimes, when I try to swipe up on the lockscreen to get the keyboard to enter my password, it just refuses to come up. Like you're showing, the keyboard will sort of semi-swipe up, but then it falls back down. I think it started with the previous build. Since the new build downloaded a day or so ago, I haven't seen this issue. But, then, it was/is only occasional. If it happens again, I'll come back here and report it.