I have a few side ops on my list that are still bright despite being checked off as completed. Most seem to get darker as you finish them.
The only one that comes to mind at the moment though is one of the prisoner extractions (prisoner extraction 3 maybe?). It still shows up on the map as well (even if not highlighted in the list) and I can still go to that location while in free roam, trigger it, and complete it again.
My guess was that this was a repeatable side op. It just seemed weird that only prisoner extraction 3 is so far, and not 1 or 2. Can anyone confirm/deny this?
Edit: Looks like a similar (if not duplicate, yet differently phrased question was already asked here. Good, additional information on the accepted answer over there as well.