edit: updated accordingly for clarity
Ah, I mean proper grammar as in formal, largely riskless grammar. For example, AI wouldn't connect
monolingual + educated + have access to technology
with pluses, like a human would.
Not sure how I'd phrase that though. Maybe "perfect, risklessly formal grammar" as I just tried to call it? (i.e. if AI trainers consider using +'es a "risk", as opposed to staying formal and spick n' span clean).
Perfect grammar is humanly possible but there is some scrutiny that can be applied to GPT-style grammar, especially in the context of the casually-toned web (where 100%ed grammar isn't strictly necessary!).