This is a bug, probably because of the something regressive going back to the days of the built-in tax liability account named Tax payable. It seems to appear in any business that has tax codes, though not in ones that do not.
I have no tax code using it and it has a zero amount with no assigned transaction. I only have transactions in GST 10% ( which feeds into GST Payable), GST Free, Input Taxed
Do not just look at or think about transactions. Look at your tax code definitions themselves in Settings. If you did not designate a different tax liability account, your tax codes could be assigned to Tax payable by default.