What causes neck seams?

[rodrigo2]

After some time away from SSE, I restarted an SSE modlist including SL & prostitution.  During an encounter, I noticed a neck seam on my PC and a slight difference in the skin shade used for her head versus the skin shade used for the rest of the body.  Any idea what might be causing this?  Note this didn't happen to the NPC she was with.

[Seijin8]

1 hour ago, rodrigo2 said:

After some time away from SSE, I restarted an SSE modlist including SL & prostitution.  During an encounter, I noticed a neck seam on my PC and a slight difference in the skin shade used for her head versus the skin shade used for the rest of the body.  Any idea what might be causing this?  Note this didn't happen to the NPC she was with.

 

1) Head mesh (usually from sculpting without masking the edges)

 

2) Wrong textures (typically the normal map)

 

3) Old/bad skeleton.nif

 

4) Custom Race and Racemenu hiccup with specular (mainly only noticeable with bright lighting conditions; fix by changing complexion in racemenu, fix persists until end of session only)

 

EDIT:  5) In the case of armors and races with different textures, this can be a failed texture swap.  Sometimes un-equipping/re-equipping the armor repeatedly will finally generate the right texture.  May (or may not be) related to VRAM utilization.