At the end of a mortgage forbearance, you are behind by the exact number of payments they allowed you to skip. With a deferment they put those payments on the end of the loan.
Mortgage companies are handing out CARES Act forbearance agreements left and right, to allow people to skip some house payments because of the covid crisis. The mortgage company agrees in November 2020 (for example) that you don’t need to make a payment until May 2021. So far that’s a forbearance.
When May 2021 comes, they can say, ok now you are six months behind!
Under the CARES Act, the mortgage company cannot demand the whole six months all at once.
But the burden is on you to “make arrangements” to pay. Congress, passing the CARES Act, expected the mortgage companies to be fair and reasonable. Congress hopes they will turn your forbearance into a deferment. But that's a hope, not a guarantee.
After a six month forbearance, you are six months behind. You are behind for the payments they said you could skip.