It's just a minor issue with the new FW that I found, but as the title suggests, when I try to reset all settings for an activity, the watch resets.
I get to see the confirmation screen, but after this follows a quick reboot (blue triangle)
I can confirm that this occurs on multiple activity profiles, but not on all (I assume some issue with GPS):
affected profiles: extreme-obstacle run, open water swim, squash, rucking, (...?)
not-affected profiles: meditation, field hockey (...?)
That's everything I was willing to test, but if you need more information, you are allowed to contact me.
EDIT (!) I just noticed that now (after the night) some of the translations of the activity profiles are missing.
I've set my watch to german and "Extremhindernislauf" became "obstacle racing" (or is missing now), "Freiwasser" became "open water" and it seems that even some profiles like triathlon are missing (see video)