In the patch notes on the Minecraft wiki, it claims that knockback resistance was changed to reduce knockback by a scale amount of the resistance provided as opposed to being a probability to take no knockback.
Knockback resistance
Is now a scale of the amount of knockback taken instead of a probability to take no knockback.
Source: https://minecraft.gamepedia.com/Java_Edition_1.16
However, if you test knockback resistance, it still behaves the same way that it used to.
Steps to reproduce:
Open up any world and type the following command:
/attribute @s minecraft:generic.knockback_resistance base set 0.25Summon a hostile mob and let it attack you in survival or adventure mode.
Observe that the player will fully ignore knockback 25% of the time.
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However, we are already tracking this issue, and this report is a Duplicate of MC-185545, which is a report that has not been resolved yet.
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