When dropping from height with a high levitation effect (high levitation effects f.e 200, make you fall instead of float up), minecrafts 'OnGround' nbt tag will start bugging out, thinking you aren't on the ground, resetting itself every second. I made a reddit post regarding the issue: https://www.reddit.com/r/MinecraftCommands/comments/qqwknf/please_help_i_dont_know_if_this_is_a_bug/