In offline sometimes it happens to mark a movie and the following message appears:
"We were unable to process this request, please try again later"
When that happens, the movie disappears from my Watchlist and I have to add it again.
This happens when connected to Trakt.
Thanks for reporting. Yes, if sending to Trakt fails once your device goes online due to an error at Trakt SeriesGuide will not try again to avoid blocking other queued actions. You will have to do whatever action again.
I didn’t know it was the default behavior for the app. Thanks 