Try not entering the policy number. I've used other software that doesn't require policy numbers and I've

e-filed returns with 2 1095A's for one taxpayer and they were accepted by IRS.

If it can't be blank, I'd make the last number on one of the policies different, but that's me, not advise on a workaround.

Also, are you sure the B and C column are suppose to have numbers? Could the taxpayer have reported an income to the marketplace that would eliminate any subsidy and just received the Insurance and paid the full premium. I don't know enough about how the "Marketplace" operates, but they usually get their forms correct.