Finally solved my issue. I don't know whether ultimately in the end it was a software problem or not. I simply redid my state return and found I had a date discrepancy which had a knock-on effect on another couple of questions. I was on hold with with Turbo-tax for over an hour before they picked up and relayed it was there fault not having the said software issue updated.
So whether it was me, or them I'm not sure. But going through the state process over again this morning and making sure info aligned is the only time I've gotten past this error message.
