devices are not available for scenes or automation, if they are in a existing scene or automation they say “unknown action”…
there are no problems listed in smartthings status page.
edit: also devices are not available in scenes. for example door locks are missing from goodbye scene.
many others have been reporting a similar issue over tHe past month. if you search for “unknown” with a date after feb 1, 2021 you will be able to see all those 
most likely related to an app update.
any fix coming for scenes. this is also a problem in automations, missing devices.
still having issues
scenes and automation, still have problem with devices dropping out (at least not be enumerated as available devices) and having unknown action followed by not available in the list to add…
still not fixed…
i see the new app has the ability to clear your setting, but i still logged out and removed the app and reinstalled. i do not get all my devices to show in actions while creating scenes or automations. in my good night scene, i don’t get the option to change modes or to lock my doors (and not all lights show up).
automations ignoring perconditions. my game room active is ignoring its precondition and just keeps repeatedly firing, over and over.
@Brad_ST can you have someone fix this:
i have a automation called Gamerroom Active, i created a location “Home - Gameroom Active” that i use to keep the automation from repeatedly from firing. So my Gameroom Active uses location “Home” as a precondition which fires a scene which changes the location to “Home - Gameroom Active”, so the Automation should not keep firing but it does. I have another scene which will toggle game room to quiet which returns location to Home…
If you’re an iOS user there is a bug that will be fixed in the next app update impacting preconditions being ignored when there are multiple “If” conditions.
Do you have a manifest for similar fixes going into Android in May’s Android release, Brad?
Found this thread after some more searching. Thought I’d just add that I have this issue with ‘unknown action’ with some devices (zigbee multi sensor, zwave inovelli lamp). Logging out and back into the app fixed my zwave locks to show back up.