I have no idea what might be the problem but it doesn't sounds right to me. It's a good thing you are taking Ruby back to the vets tomorrow. I understand you like your vet (as I like mine, too) but Ruby might need to see a specialist if he can't figure it out. I don’t know what kind of specialist though. Maybe one of the breeders here can point you to the right direction. I hope it's nothing too serious. Please keep us posted.