Is that inside a door?  Hard to tell from the photo without context.  

I would also say no.  Looks like that might be a join, so also think it's movement/shrinkage.  Probably easily fixed with some sandpaper and touch up paint.  

Looks like the edge/seam of the door. If you press gently with your fingernail on the spot, does it move in slightly?

If so, it'll be the sealant under the paint which expands/contracts slightly due to temperature changes.

Rubber type sealant is used between the inner and outer door frames/panels to prevent moisture ingress between the two. They're seam welded, but the sealant is a guarantee that nothing will get between them. This area is fine without paint by the way.