Can no longer drill down through the Test Suites


We have recently upgraded our TFS installation to SQL Server 2016 (from SQL 2012) and the Test Plan Status report seems to have lost the drill down button [+] for the nested test suites so it is no longer possible to drill down through the nested test suites. The test suites labels are missing for the nested test suites too. Seeing the same issue in Chrome, IE & FireFox. (The upgrade has updated SSRS as the reports are displaying with a new skin.)