Zombies summond with some spawn events are to fast

summoning a zombie with some spawn events like minecraft:start_death will move very quickly compared to normal zombies.
to reproduce:
1. run the command /summon zombie ~ ~ ~ minecraft:start_death
2. run the command /summon zombie ~ ~ ~
3. compare outcomes
observed result:
the zombie with the spawn event is significantly faster than the one without
expected result:
both zombies move at the same speed