(sorry - I tried posting before and screwed up. In case it’s not obvious, I don’t know my way around here!)
I believe I have the same issue of an activity that was previous complete now incorrectly showing some incomplete nodes. My user number is 103223, the activity in question is 91161729 and the corresponding Strava activity number is 17745214963 (I tried posting links previously and that didn’t work).
I had paused Strava on this activity, driven to another location and then unpaused - the only time I did this. In case that was the reason, I cropped the Strava activity and attempted to sync. That hasn’t worked. Thanks for any help you can provide. If it was a shorter activity, I would have just gone and re-done it.