"are you sure your client didn't talk to the marketplace or was listed with a separate taxpayer on a plan?"

Yes, I double- and triple- checked. I, too, have had clients who swear up one side and down the other that they don't have marketplace insurance. I ask them to bring me their insurance material, and they bring me their 1095-A, and I say, "Okay, this is marketplace insurance," and they say, "No, this is Obamacare."

Insert eyeroll here.

I did have one client who was going through a divorce. My client was not in the home, and they couldn't get the ex to provide my client with the form that was mailed to them. My client tried calling the marketplace directly, and they refused to provide my client with a digital copy, because he couldn't answer the security questions which the ex had provided. So there was no way my client could get a copy of the form. We had to paper file, with an explanation of why we weren't attaching the form. This was pre-Covid, and it would have been nice to have this option to bypass.