Video doorbell v2 with firmware and app up to date on android will not hold its sensitivity settings. I turn sound off and usually put motion to 46. After a few minutes it will default back to 50% on both causings continuous notifications. Now I have to turn notifications off and it defeats the purpose of having a doorbell cam. This happens on 2 seperate units at 2 seperate locations. Only happening with my doorbell v2s.
Since it happens on two separate doorbells at two locations, I would suspect the app or firmware syncing the setting rather than your units. Try changing the sensitivity once, then fully close the app and reopen it to see whether the new value is still there, and check the same doorbell from a second phone if you have one. If it still snaps back to 50%, submit a log from the app right after it resets and mention both doorbells and the exact firmware version to support, since that makes it easy for them to reproduce.