Noticed this in passing a few weeks back but forgot to take a picture or mention it.
Lap Swimming with latest firmware (4.16) the scrolling workout summary (shown after stopping the activity but before saving) shows a funny Average Pace value. I think it may be Elapsed Time (including rest) / Total distance Swam.
Example:
I swam 3300 yds in 58:13, the screen before pressing save cycles through and shows Avg Pace 1:45
After saving I can see on Garmin Connect and the watch summary screen that my activity was 3300 yds, 1:29/100yd and 58:13 total time.
Not a huge deal, but the few times I noticed it I thought "what happened to my recording, that's way off" until I realized what it was doing (inconsistently) and it seems like another bug.