Reading http://docwiki.embarcadero.com/Libraries/XE5/en/Data.DB.TField.OnGetText it looks to me like it is meant to work like DevExpress have done it, though I don’t understand why if I put something on a grid column to specify a format, then it doesn’t use that but they assume the DB field’s formatting is to overrule that.
I logged the same issue when it first popped up in builds after .71.1097 (RO #65455 and #65492 refer) after I’d logged a question with DevExpress (Q555207) and they’d convinced me it was the data table where the problem was. Now I’m not so sure, even after reading EMB’s docs.
I also notice OnGetText (and probably OnSetText also) in Delphi which was around the time the issue popped up, not sure if it’s related.