Sometimes the added signer isn't the one that should sign the document. They can then transfer their signing rights to the correct recipient. If you don't have Transfer Signing Rights as a default in your settings, you can always do it on a per-document basis.
A recipient can't transfer their signing rights to an already existing recipient of the document. If they wish to do that they will need to contact you, the sender. You will then have to create a new version where you correct the recipient roles.
How to enable signature transfer in the draft action menu
Click on the draft action menu
Tick in "Allow signature transfer"