Yes, I've experienced the same error. Posted about it here but no acknowledgement yet. My repayment limitation is listed as $1350 (which would the correct value for 300-400% FPL) despite my AGI being six-figure (well above the 400% FPL limit) and total subsidy being $4972. I've double-checked and even re-entered the income and 1095-A values. Also verified that this is not simply a TurboTax display issue -- the tax due is truly being calculated with the $1350 (or in your case filing jointly, I assume, $2700) value. Discussed with the IRS and they agree with my interpretation so seems to be nothing to do but wait for a TurboTax fix or file elsewhere.
