Alexa Skill not able to find new devices

That one is several weeks old, I think the newest is 2.4.0.201812011454.

You can find the latest one at the top of this thread. Maybe updating will resolve your issue.

I see your still on OH version 2.3, you might want to update to something like 2.4 M7. I recently updated to M7 from 2.3 and so far no issues other than needing to stop OH, clean the cache, and reboot.