I have created one field Activity completed date (formula field) to calculate the Activity start date and when user checks checkbox as true needs to know the date of Activity completed date. So my formula is Activity completed date = IF(Completed_Meeting__c = true, TODAY(), null). It works well but whenever the user loads the records it's calculating again and putting today's date even though the user checked the checkbox yesterday and no action taken on that record.
I cannot use the ISCHANGED function in formulas, and for a simple requirement I don't want to go with Flow.
Any suggestions please? Thanks