An update: I was able to find a workaround (on my own - no support was ever provided for this issue).
TT automatically populates Schedule 1, Line 17 with data from form 8962. This includes the premiums you pay in an insurance exchange (from form 1095-A). TT also adds any health insurance you claim as a business expense (calculated on form 7206). This can lead to double counting. How to reconcile this will probably depend on your specific situation and whether or not you claim the premium tax credit.
TT (online version) produces no warnings for this issue, no explanation is provided on the tax return, and messaging / explanation of where to claim these expenses is minimal. This ended up being a huge time sink and I suspect some filings will be inaccurate as a result. Shame.
