User blog comment:IBandGHrules/Luke was Fluke all along./@comment-27393649-20150228170024

They kind of already have given a thorough explanation. If Luke isn't being mind controlled, and it is pretty clear he isn't, he's changing his own personalities. On the day with the episode (I forgot the date) He was nice and cuddly to Tracy and then snapped back to rudeness after she brought up his family.