the skeletons and pillagers don't attack player because /data merge repeating command

I needed a monster whose data kept changing.
However skeletons and pillagers don't attacking player when they's data get merged

 

What I expected to happen was...:

they's data was keep changing merged,
skeleton have to shoot me,
toolless skeleton should be hit me and
pillagers have to shoot me, too

 

What actually happened was...:

they's data was keep changing merged,
they can't attack me that moments at

 

Steps to Reproduce:

1)

Install repeating command block, and that commands input "/data merge @e[type=~~~] {Health:20}" (Is NOT need to be Health data command)

 

2)

you're gamemode need to update to adventure or survival, turn on repeating command block

 

3)

check the entity's attacking players, when turn on repeating command block and before