The bug
24w06a introduces minecraft:fall_damage_multiplier, an attribute that can be used to change how susceptible a given entity is to fall damage. Setting this to zero will forbid that entity from being damaged by falling. However, it being a greater value than zero will not permit mobs normally immune to fall damage to receive it, and mobs immune to fall damage have it set to 1.0 by default, which is unexpected.
Affected entities
minecraft:blaze
minecraft:cat
minecraft:chicken
minecraft:iron_golen
minecraft:ocelot
minecraft:snow_golem
minecraft:wither
I am not sure if flying mobs, or non-mob entities, should be included here.
How to reproduce
Spawn a cat, ocelot, chicken or other mob unaffected by fall damage
Run the /attribute command to get its UUID and query its generic.fall_damage_multiplier value
Expected results
The value would be 0.0.
Actual results
The value is 1.0.
How to fix
Make all cats, ocelots, etc. susceptible to fall damage if the attribute is not zero, and have this attribute set to zero for them by default.
Merging into MC-270116.
Ownership was granted of MC-270116 after asking in discord so these reports can be merged together