Not sure if this is a bug, or by design..so just want to check really.
Does the issue occur in the editor or during gameplay?
gameplay
If it's a gameplay issue, please specify which movement system and camera type you're using (free movement vs. grid movement, third-person vs. first-person) or N/A if not applicable:
Free Movement, Standard
Briefly describe the issue you're experiencing:
With Collision Debugging View on, the player version of a model does not have the custom collision set on the model, compared to an NPC version of the same model. (See Image below)

Base_justin with the big collision box is an NPC placed on the map.
Base_justin with the collision that tightly wraps round the model is the player.
Same model file.
Are there any errors in the in-game debug console or external console window?
No
Provide the steps necessary to reproduce the issue:
- Set a character model as player
- Add custom collision to that model
- Add a instance of the model as a NPC (no behavior)
- enable collision debug view
- play the game and observe your collision VS the NPC