My billing page says Pending due a date on one invoice and credited on another. What do they mean?

An invoice raised under a signed agreement reads Pending · due with its date until it is paid, and Overdue once that date has passed. A POS add-on invoice that a credit note cancelled reads credited, with the credit note's number beside it and a dash in the date column. Every other row keeps its ordinary status word. The Account, trial & billing tab in the docs covers the billing page.