the chunks i explored are on y level 127!

I exported a bedrock world from 1.16.221 hotfix to 1.17.0.50 beta and i was playing on it for 3 days and it was fine but suddenly one day the caves and cliffs toggle got unselected and the chunks I have explored are on y level 127 and the chunks i havent explored are normal. The water was glitched and wasnt flowing and all of my pets got suffecated to death because when i logged off i was on y level 69.