We had an operator manually release a workflow breakpoint too soon. The breakpoint was on the 11th job in the workflow, and the first 10 jobs had not finished executing yet. What happened next was a total surprise to me... it released the 11th job (and then its successors) immediately, instead of waiting for its 10 predecessor jobs to complete!
I now think the operator must have clicked the "go immedeate" option which is right next to the "delete breakpoint" option.
Anyway, I now plan to find all of our breakpoints and replace them with CALL STANDARD objects to protect our operators from this type of human error.