This happened to me! When I inquired about a horse, the owner called him an Anglo-Morgan. I thought 'never heard of that' but assumed that it meant TB X Morgan. I did buy him and when I was looking at his pedigree it turned out he was an Anglo-Arab, ah that was more normal! And I thought he looked Araby. Turns out Anlgo-Morgans are being bred, but they are not yet a 'recognized' cross breed yet, they are reasonably new.
Ive had 2 people that have been around drafts all their life and BOTH swear up and down that he is a FULL Perch.
Seems like no one really knows...but everyone tells me they do not see Belgian AT ALL...and no QH either.
His coggins papers say half belgian, half perch....but it coulda been a stable helper at the time who just made a guess when the vet was filling out the paperwork...So you really don't know.