When a player steps over a sticky piston with a fence while the piston is retracting, if there's enough space around/below the piston, the player will be teleported over there.
It seems to be a different issue than [MCPE-175206] since that was marked as resolved, and the consequences are not the same. It also seems to only happen when the piston is pointing vertically upwards.
It happens both on vanilla servers and in single-player.
Linked issues
Comments 2
We're tracking this issue at MCPE-169011, so I will resolve this ticket as a duplicate.
Hello When a sticky piston pointing vertically upward retracts while the player is on it and a fence is connected, the player is teleported to nearby spaces, either next to or below the piston. This happens if there is enough space around or under the piston.