I upgraded to IoX 5.8.3 on Friday, which had no effect. Then I created a new state variable and contact sensor on Saturday but it didn't work. However, on Monday morning, I noticed that one of my routines started working again. After that, I noticed other sensors returning to life over the next two days. This morning I finally had a chance to test all my Alexa sensors, which are all finally working again! I don't know if it just took the update a few days to take effect or if Amazon finally got to my ticket and fixed it on their end. Either way, I'm back in business. Thank you all for your help and best wishes to everyone that we have put this issue to bed.