CTS is not dependent in the firmware in itself.. yes the actual firmware needs to pass, but all of ours pass before we FOTA. Then there could be some issues where the sync with Goog servers could have faced som eissue.. I don't know.
In this case it seems many of you report CTS / SafetyNet is working now. As such we'll mark this as non-issue from here.
You may also try to clear the Google Play Store app cache (long-press Play Store icon, press " i " , Storage & Cache. Clear storage.