When on a cheats world in survival mode, if you change your permissions, creative flight is sometimes possible. The opposite happens in creative mode, flight will sometimes become impossible. The only way to fix these is swapping gamemodes and swapping back.
Steps to reproduce:
Make a new world with cheats on, in creative
Change to Survival mode
Change your permissions in any way
Flight should be possible in survival
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We're actually already tracking this issue at MCPE-67688, so I will resolve and link this ticket as a duplicate.
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