Tyler Adam Terry Davies

if it locks you out make the world then copy it then do the /fill command again and then see what happens it never happens to me with me and my alt on the same world so retry although im playing terra swoop force with my alt and your useing farm life so it might be the map

This is a version bug im on the java demo if i open to lan then activate cheats i type /give @p glow item frame in any version it wont work 

When Minecraft is minimized it will disconect you from your server but you can rejoin the bug would be you not being disconected on multiplayer worlds cause that happens aswell (on bedrock) (i play bedrock)