Giving the player a jump boost effect, removes all fall damage, regardless of the amplifier. To replicate, /effect <player> 8 15 10, Then jump, no fall damage is observed.
Comments 6
Its probably not causing the problem, but just update your Java version as it may cause other bug-like situations.
Jump Boost adds a fall damage resistance effect to stop players from taking damage from higher jumps, and the more potent the effect is, the less fall damage you take. Works as intended.
Not intended as it is mentioned in the description that all fall damage is ignored when the effect is active disregarding the amplifier.
Cannot confirm.
The fall damage is reduced while having jump boost , but not negated.
Issue
/effect @p 8 150
/tp @p ~ ~20 ~
and see how you get damaged, but less damage than without jump boost.
Amplifiers above 3 (Tier IV) are not supported, see MC-10755
confirmed