5500 for Trust w/forfeiture balance but no participants?

In prior year, terminated plan paid out all participants, but apparently there is a remaining forfeiture account that had to do with incorrect contributions to participants (not due to unvested participants).

Recordkeeper/TPA was supposed to use that forfeiture account to pay for closing fees.

Fast forward 9 months later and that forfeiture account is still sitting in the trust, when the intent was to file a final 5500 for that prior year.

Seems like 5500 is to be filed showing zero participants but with a balance, but I just don't know.