It’s not that starting balance have lost its minus. In previous versions, many users had starting balances established as one big journal entry. In some cases, this journal entry would have so many lines that it was impossible to edit.
To address this problem, a few days ago I wrote a migration script to convert this big journal entry (if detected) into a series of starting balances. Credit balance within that starting balance journal entry should have been converted to negative starting balance for bank account unless that bank account has been in foreign currency. I think this is what’s happening, for foreign currency bank accounts, there was a bug which would result in loss of negative sign.
Can you please confirm these bank accounts which got unreconciled due to starting balance losing negative sign were all foreign currency bank accounts?