So, I'm pretty sure it depends what difficulty your world is in:
easy- 0% chance they become zombie villagers
normal- 50% chance they become zombie villagers
hard- 100% chance they become zombie villagers
Translation if needed:
The arrows with effects don't work
When you add effects to the arrows, it does not affect those who you use the arrow on.
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Pretty sure its duplicate
Duplicate: MC-107856
I think a couple other people have reported this already, this is the issue that is being tracked i believe: MCPE-67169