yes it is an error. if I uncheck the box I would be lying as I am not married. I co-own the house with my partner and we file separately. I paid for the new boiler and wanted to claim the entire credit and she will not be claiming any credit. So the 600 credit to me seems appropriate and this is what was submitted by turbotax and the return was rejected by both the IRS and State. This has never happened to me.
