Well, if it helps any, I've had a single playback camera screen up for most of the day on UI3 - paused. When I clicked the X to go back to live, I got the live camera immediately. I did nothing else, and within a few seconds I got the "player stall" error. It was 1:1 on the zoom, and no input. I suppose it's possible that after sitting for hours on a paused playback clip that it some how lost its bearings?I didn't change anything related to layouts in 201-203, but it is possible you were just remembering behavior in 197-199 and did not actually see it broken in 200.
I will adjust the "stall detection" again for version 204, and make it wait a little longer for signs of activity before declaring the video player dead.
720p @ 5fps and single camera views should stream perfectly. If you open "Stats for nerds" it will show you the network delay and the player delay, that is a clue for the source of the problem. Network delay could be anything from the network or Blue Iris or even a camera problem. Player delay is 100% internal to UI3 so if you get a lot of delay there it could be worth changing the H.264 player choice in UI Settings.
Thanks for your help.
ETA: I'm not on 204 yet. This is still 203 from last night. I was just commenting that it didn't involve any zooming. I'll jump to 204 and see what happens.