Navigate the Workflow Cleaning tab on the Troubleshooting and Support screen and click Remove Approval Condition in order to remove all Approval conditions from all transitions of each workflow.
If all workflows have been successful cleaned a message informs.
If any workflow has not been successful cleaned a message indicates the list of workflows still affected by Approval Conditions.
It is expected that on uninstalling the add-on the Approval Conditions are automatically removed and this operation is suggested for troubleshooting exclusively.
If you have removed the condition from the workflows erroneously, you can restore it by running a re-indexing.