@dmerz Thanks very much for the response -- finally an answer that makes perfect sense.
Nevertheless, this is really unacceptable from TurboTax — at no point have I ever seen this described/explained by the software, and even TurboTax people I've called about it have said they have no clue, or know this is the case and obfuscate. The issue with not telling TT that I got Marketplace insurance is that it is a lie and, presumably, the IRA receives 1095-A directly from Covered CA. Thus, since I have had Marketplace insurance since 2014, such a change opens me up for auditing. Additionally, TT supposedly "guarantees" that you are getting the best possible refund, which is obviously not true since this issue has cost me several thousand dollars over the past few years.
Still — your response has finally given me a logical answer to this puzzle. Thank you!
