Using /effect [player] minecraft:[effect] [time] [value] with a value over 127 results in odd behaviours of some potion effects. The one behaving wrong that I've found are "levitation" and "jump boost". The problem is that those values seem to be saved in a byte which results in negative numbers.
Having the effect "jump boost" with a value greater than 127 results in the inability of jumping because the game tries to boost the player into the ground. Having the "levitation" effect results in a funny supergravity to slow motion fall effect. The value 255 results in the ability to fly without the creative mode - you simply can't choose your height.
Another issue that won't happen if these bugs were fixed is: If you are in survival mode, the effect levitation with the a value greater than 127 wears off and you fall down and are being damaged, you are catapulted 61 blocks into the air. For me it looks like a collider issue because the height you fall down from does not matter.