its most likely lag. sometimes they do sometimes they don't. If the zombie is really close to you when you run into a house and close the door the zombie will hit you while its at the door. If the zombie is farther away and you close the door it wont get you.

well it does z can be at the door im upstairs and still get hit

Hello gooner1010 and thank you for the report.
This is an issue we are aware of and it has been scheduled for a fix.
Regards,
Geez