I'm not aware of any issues in that regard, although I don't have any personal experience. Is it possible that you have any screen management software running that might be affecting other windows when streaming?
Please enable logging (Configure > Options) and restart PT4.
Go to File > Open User Data Folder and navigate to the Logs folder.
Reproduce the problem (start streaming) and then attach the PokerTracker4.log file to a
Support Ticket before you start PT4 again.
I don't expect this to tell us all that much but it may give us a clue as to whether PT4 is crashing or being told to close, for example.