More details: It doesn't always kill players when they teleport. Using operator's /tp command will also sporadically generate a kill.
I have also had this issue. I confirmed it multiple times with multiple players. It began with the update to 1.16.100 on 11/19/2020. (We didn't install it on the first day.)
More details: It doesn't always kill players when they teleport. Using operator's /tp command will also sporadically generate a kill.