Coonans have always been a bit out of spec, but not in a way as to affect function (the most obvious one was purely cosmetic, i.e. the gap between the bolt carrier and the receiver, due to the different way they machined that area compared to OEM receivers). From what I understand, more recently, as in the last year or two, their QC has gone downhill at least as badly as DSA with their in-house cast and forged receivers, and that has been combined with a refusal to make anything right for any defect; basically, no customer service once the sale has been made and the receiver delivered.
Sadly, there are no longer any manufacturers offering new FAL receivers for sale in the U.S. that are of high quality and fully in-spec. LMT could do it, but they would need legitimate blueprints and cannot legally use what DSA provided to them when they were contracting LMT to make them (Steyr blueprints which utilize the specs provided by FN; DSA bought them from Steyr); at least that's what they told someone who inquired about having some made.