The reporting, or the non-reporting, of the mortgage has nothing to do with the BK. Each creditor can decide if they want to report or not. It's totally up to them. They can report on one of the 3 CRAs, 2 of the 3, all 3, or none of the 3. Their call. And if they report, there's no legal requirement to keep reporting. They can delete early if they wanted to. Without knowing more, it's possible your mortgage never reported. Or if they did report, maybe they decided to delete after the BK.
Per FICO, the deletion could have helped or hurt you. The only way it could hurt is if the age of the mortgage was greater, on average, that all of your other accounts. In other words, deleting an old account can sometimes hurt your average age of accounts (AAoA). The deletion could have helped your FICO if it was reporting any lates and/or reporting a "included in BK" comment. Both of these scenarios would hurt your score and your score could have increased when deleted. Any IIB account is viewed as a negative. It's deletion could have also helped your FICO if the mortgage was younger than your average age of accounts, meaning the deletion would have elevated your length of history.
