Another someday job - ceramic tiles were about to pop off part of the kitchen wall, so I carefully removed them, lest any be broken. Must have been some sort of shrinkage or movement somewhere to cause them to do that.
Not sure how to deal with it. Take the lot off to the corner and trim a smidgen off those in the corner? Or just try and stick them back with a narrower gap between them? They had the wee plastic cross-type spacers between them. Will have to remove all the old adhesive, and sort the wall surface.