In multiplayer over WiFi mode, this glitch happens to players connecting but tnot the host. When descending down a ladder, damage is taken . You need to begin climbing down, then, partway down, jump off slightly. Re enter the ladder further down, then climb to the bottom. You will take the amount of damage you would as if you fell the distance then hit the ground.
If you did not already, please remember to perform a search before creating a ticket to see if your bug hasn't already been reported.
This issue was reported previously as MCPE-8742. Comment your experience there!