Sometimes while playing in creative mode and you're inside a structure your head will go into the first block of the ceiling if you rise up. It doesn't stop you once you get to the ceiling/ first block like it should.
It doesn't happen all the time but occasionally.
Thank you for your report!
We're actually already tracking this issue at MCPE-43767, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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