To my knowledge, the custom kanban functionality is no longer being developed or supported. It is one of the reasons I recommended that you not use it at all. Although, in the Release Notes for 10.55 (dated September 2019) they do mention a slight update.
You can always open a defect with Jira Align support to see if they are actively supporting custom kanban functionality and if they will fix the cumulative flow metrics.
I recommend you focus on the backlog kanban functionality and the value stream/process step functionality.
(Or, What to expect when you’re expanding.) Once you've completed your Jumpstart, or your initial assessment of Jira Align, you'll start to think about how you can roll it out to the rest of your e...
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