This will be caused by a profit and loss account, Major heading code nominal account having a Year end code set to a wrong Nominal code, as such when a Year End is run the profit and loss account is cleared down into that wrong account.
To resolve, you will need to journal the values from the incorrect Nominal Year end account into the correct Nominal Year end account.
After that you will need to change the year end code on the Nominal account so it is cleared down correctly next time. To do this:
Click Financials, Accounts
Select the Account that needs amending
Click Edit
On the Settings tab, update the P&L Year End Code to required Nominal Account
Click Save.