Sorry @suect1987. I looked into this a little more, and you were right, Form IT-558 does apply to COVID-related retirement withdrawals, as per this post: https://ttlc.intuit.com/community/state-taxes/discussion/what-is-new-york-state-form-it-558-turbotax...
Still not sure if that's where the state filing error is happening, since people from a bunch of different states are seeing it (not just NY), but yeah, maybe that is part of it. I just hadn't heard it referenced as the problem, but rather the transfer of info from federal 8915-E to state 8915-E.
