I had a power failure that caused a z-wave switch to lose z-wave connectivity. To bring it back I excluded and re-added the switch. Excluding a device that was part of an existing Scene caused a nullref error on the Scene edit page:
2021-07-11 08:50:43.712 [error](http://192.168.1.139/installedapp/configure/14)java.lang.NullPointerException: Cannot get property 'currentSwitch' on null object on line 594 (mainPage)
Because the scene was now un-editable, the issue was impossible to fix without deleting all scenes and starting over completely. Quite a waste of time.