I had previously read these recommendations and have followed them, specifically, I have cleared my cache, deleted my intuit cookies, attempted to run in different browsers, including in Private and Incognito mode. I also had another user in my organization attempt to edit a custom report group and they had the same experience. 

I believe I am impacted by known issues regarding the edit button in custom reports in QuickBooks Online and should be added to the list of affected users with this investigation number: INV-95333