the bug is happening because in first person mode your head and helmet are removed. If you use a camera mod to look at yourself while in first person mode your character will be headless. When you load a new area it loads your full character and the camera is placed inside your face so depending on your character model and what you have equipped you may see your eyebrows/beard or parts of your helmet. when you switch to 3rd person and then back to first person it removes your head/helm again so you don't get the issue.
A fix from TW would be to do a check on the camera settings during load and not load character head/helm if set to first person.
