This has been going on for awhile, so I can't pin down when I remember first seeing it.
Often times, I get more than one notification window at the beginning of a turn. I get a brief glimpse of them, but then only the very last one remains, and I can't ever see what it overlaid. The very last one is the only one I can make a choice on (if presented to me).
That is, it appears that the notification window buffer / mechanism is getting multiple events, and rapidly displaying them, but the next subsequent even overwrites this buffer, and thus, you only really get to see/interact with the last event.