Any overflowing levitation effect on players (Higher than amplifier 127) forces the OnGround tag of the player to 0b for a few seconds after the effect has worn out. This might also be the reason why the jump statistic breaks during this period as well. Here is how to reproduce it:
Run the following command:
/effect @p minecraft:levitation 5 128 (128 can be higher, too)
Shortly after landing, run this:
/testfor @a[r=0] {OnGround:1b}
The expected behaviour is for the command to return your username. However this isn't the case.
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Effect levels above level 4 aren't officially supported. (Not supported as in if they cause issues, it is your problem and not something Mojang will fix.)