Two companies - payment for invoice to wrong account + owner then transferred

Fawn

We have/had a sole proprietor business and have now transitioned to an Inc company. A customer incorrectly paid their Inc invoice to the old sole proprietor account by mistake. The owner at the time then transferred this amount from the sole proprietor account to the Inc account. I have matched up the transfer into the Inc account with the invoice there but am unsure as to how to categorise the outgoing transfer from the old sole proprietor account?