I have a checking account with a transaction showing a deposit from a mortgage dated 2/18/2004. When I click on "Go to matching transfer", I see the mortgage account, which which was opened in 2012 and obviously shows no corresponding transaction. If I try to delete the phantom checking account transaction, I get "This transaction is a transfer to a split and cannot be deleted here." If I search for the amount of the transfer, nothing shows up other than the phantom transaction in the checking account register.
I have tried Validate and Repair multiple times already.
How can I figure out what this transaction is for and how I can delete it?