I am an accounting clerk, In my opinion yes you will have to pay tax on your reimbursement. Due to the fact the govoerment has sent you the form for it I would think they want their money. It might be considered income. I would double check with a tax service, just to make sure. There might be a clause that in the agreement that would affect the amount of the tax rate.
Due check on, you don’t want any problems with the IRS.
whiskey Girl