@Caroline “Output stream end encountered” error indicates that client received end of websocket stream for some reasons such as connectivity issue or server error. If the pull replicator can recover after retry, it should be fine in general.
Can you cross check with the Sync Gateway log during the same timeframe to see if there is an error on the SGW side or not?
I couldn’t confirm if it’s the same issue as Document no update after reactive from background (iOS) or not. It could be the same or different.