when I'm finishing a swim there two small issues. First the bpm are not shown in the graph (also later when you open the activity).
Also when the details of the activity are shown the rest time is always 0 hrs. First I thought it wouldn't be calculated but this time I made pictures and a video. Also it was easier as rest time was already at 0 and after the swim it was 21.
Picture before I started:
Video saving the activity (was too big to post it here):