Tiles used not vined but not disappearing

Kassi_Maurer

I have this problem where I create a word and it only takes away some of the tiles. Usually it leaves 1 or 2. It doesn't happen everytime. Does this have to do with word length or something? And these are non vined tiles. I understand about vines. These look normal. Help! 

StuckInATree

If they are not entangled in vines they should be disappearing. Personally I'd record it and post it on here, if they are totally normal tiles then it sounds like a bug.