We often hear the question - In Kanban, what should we do if a User Story in Test column is found to have a bug that needs to be fixed? Let's say the workflow is something like this: Todo -> Development -> Test -> Release. If a User Story has completed Development and moved to Test, and a tester finds a bug, what should we do to that User Story? Is it right to leave that User Story in Test and the developer should stop their current development work to fix this Defect first? If so, does this mean that developers must be interrupted all the time to clear the bugs found in Test?