This is an outside corner where the molding pieces gapped. A little caulk will fill in the area nicely, and following this up with the same faux finish will take care of the rest.
 You'll also notice that I left the nails only partially driven.  Ring shanked panel nails have a lot of grab, almost too much at times.  I've learned not to tap them all the way in until I'm 100% positive that all the moldings are just the way I want them.  This makes it easier to pull down a piece if it needs to be repositioned.  If the nails were all the way in, the molding might be torn to bits, and all that faux finishing (plus the initial $29.59 price) would be lost.