Superflat Custom Presets Not Working

this bug makes it so that custom superflat presets do not save, and reverts to the default superflat preset. though, standard presets (like redstone ready), do work. I have tried multiple custom presets, and all of them didn't work. I have gone back to previous 1.14 versions, and have found out that this bug started to appear at least in 1.14.2. I hope that the people at mojang / Microsoft will be able to fix this issue. Thank you for your time