After getting a few nice compliments on the panel wainscoting project so far, I feel I should probably fess up to a little mis-nailage that occured. Since the wainscoting cap sits on top of a 1x4, I nail (with a pneumatic nail gan) from the top to secure the cap in place. I'm not sure what happened here. I just didn't align correctly or something. I've been trying to push through, pull it out, nail it back up and it's just not budging.
So, I guess I'll just leave it as a conversational piece.