it could be that your router has a password, if you are connected to your wifi but do not have internet on it its your actual wifi at fault not minecraft, if you have signal boosters they also sometimes will connect to your device and not give out actual internet, if those do not fix your issue try reinstalling the game
if you wish to back up your worlds youll need to use external programs, there are videos on youtube just search
how to save worlds as ,mcworld mcpe
or something like that
if you wish to recreate it place a sticky piston with a block on it against a wall, and constantly try over and over
the method used also surrounded other sides with blocks to force the game to push you through the border bocks
the world is ran on mcpe but is possible on all versions as far as personal testing goes
This is what it always has been called, its not a glitch or bug its just mojang being mojang
its a feature