I’ve seen that exact same thing happen twice before. Both were because of damaged NM cables in the walls on new construction. The neutral and grounding conductor where mashed together in the wall. Luckily these were not on my own jobs, but I still had the unfortunate task of locating the problems for someone else.
Sometimes the grounding conductor and neutral are touching somewhere downstream in one of the receptacle outlets. It could cause AFCI tripping when a load is applied, meaning something is plugged in or a light on the circuit is turned on.
