Sometimes, in creative, I try to see what entities are alive because of my commands (/say @e). The chat says, "selector @e found nothing" - not even me. I can still be found using @a or @p and the bug persists even if I quit the world or Minecraft and try to re-open it, but stops as soon as I try to kill myself (/kill @p)
Each time I was multiple thousands of blocks away from the world spawn, if it can help
(Sorry for the eventual mistakes, I'm not a native speaker by the way)