How to calculate a date and maintain the record

em_amdahl 

I don't think it is possible using the SharePoint calculated column formula because every time you edit/update the list item (any column value) or calculated column formula itself, the calculated column formula will execute and overwrite the previously saved date value (TODAY() - when status was changed) in the column.

I think you should use the Power automate flow for this:

1. Create a date column in your SharePoint list
2. Create a new flow which will run on item creation and update (When item is created or modified trigger)
3. Add trigger condition based on date column so that the flow will run only when the date column is empty
4. Inside your flow, add "Condition" action to check if Issue Status is equal to Acknowledged
5. Inside "If yes" block of condition action, use "update item" action to update date column to current/today's date using utcNow()

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