lol - don't worry it's a she, yep a 16hh Tb (not known for great heels), so possibly that's the reason. I worry a stone will get caught between back of shoe and actual heel.
my farrier does this to my girl as well as she has not got great heels, it just gives a little extra support. I've never had any problems and never had a stone caught in them
My farrier did this on my 16.1 TB, he has no heel on backs, never got stone caught, just straw slipped in between but pulled out easily. Now gone barefoot anywhay cos couldn't get over the damage shoes were doing to his feet. Amazing difference in hoof quality.