As I wanted to treat a particular approval as optional during a workflow step, I removed this condition
Check Approval Condition - Users can execute this transition only if the configured Approvals are already satisfied.
... from the transition to allow users to move on to the next step regardless if the approvals have been fulfilled or not.
This worked perfectly until we did a restart and promptly found that this condition rose from the dead afterwards.
Is there a configuration somewhere I'm missing or this is something that the add-on is designed to do which is put the approval condition on all workflow transitions it sees?