I'm trying to apply kanban to a team that has a specific process workflow designed by the client to deliver items.
I'm facing some struggle on a specific step that requires an item to be modified by a team member and then running an evaluation step that requires some waiting time. Based on that evaluation values, there is the need to go back to the modifying item step, and rerun again the evaluation, and stay on this loop until we are satisfied with the evaluation values to advance to the next step.
This evaluation step has a lot of waiting time (depending on the size of the modification) and the application that runs it is not stable, so it is really important to show the impact that it does on our flow.
Based that we shouldn't go backwards on a kanban board, how should we be able to tackle this loop step?
Edit based on replies: On those 2 steps that we have the loop, one is work in progress, the other is relevant waiting time where the team member can pull other kanban card.