Put the summary of the bug you're having here
when a llama is attacked with any sword, or axe heart sprites appear. there are no apparent sprites from any other strikes with any other tools or weapons other than swords and axes.
Comments 2
I believe this is intended behaviour. The hearts are the darker shaded damage hearts, and is the same when attacking any mob.
These dark heart particles are shown for living entities when the player attacks them and the damage is larger than 2.