This bug affects a player's ability to fly in creative mode. Doing the classic 'punch the jump button twice to fly' isn't the problem. The problem is that once a player does take off, there is no way to land save switching the mode to survival and then back to default. Below is an example of this bug through a copy link: 

https://1drv.ms/i/s!AmbeojZebIeyge56SZQ6xRSPN9PxSQ
It shows my avatar in the first person camera flying in a lush cave (I was trying to fix up the mineshafts in it) but the button on the middle right that allows a player to stop flying is gone. I have tried playing without any texture packs, but it seems to be a purely vanilla Minecraft issue. Any assistance to squash this bug would be appreciated. Thank you. My best recommendation to reproduce this glitch is to load into Minecraft Bedrock on an iOS or Apple device and use the standard trick to start flight. If it helps any, the way this glitch behaves reminds me of what the Rasberry Pi  version will do, where one double taps on the space bar but can't get down. Thank you for any help.