Passengers can get through OUT gates, but not through IN gates.

Passengers that are heading to the platforms (yellow) get stuck at the beginning of the IN gates. Some of them (lets say 1%) manage to come through, but most of them can't. Meanwhile, passengers heading to the station exit (blue) have no such issues.

Note that:

1. Both IN and OUT gates have the exact same properties.
2. The corner IN gates are as wide as the OUT gates.
3. Passengers that are trying to go in are the same types as passengers that have managed to go out
4. Passengers with big sizes have managed to get out, so size must not be the issue. 
5. There are no obstacles in the way, i have checked.

What could be causing this? I have uploaded my models (via secure file upload) in case it helps, or i can send them via email.

Thank you in advance.