I can't find a solution, so I'll try here to see if anyone has had something similar happen to them on the Fenix 7 SW 14.36.
Yesterday I ran my third "Garmin Trainer for 5km Plan" run (one "Comparison Run" and two "Repeat Walk/Run"). At home, however, I discovered that even after the watch reported that the training was over, it was not recorded in the plan as having been completed. So I thought to myself, well, I'll run according to the changed plan today and hopefully it will even out. But after today's run, he entered the plan, but according to the plan, it looks like I should run one more time. And what is even more special, the run from 12.9 was removed from the plan as completed.