Apple released new OS updates a couple of days ago. No mention of any improvements to HomeKit.
I started with updating my iPhone first. I noticed a HomeKit automation where a scene involving HomePod appeared after disappearing several days earlier. I then updated the HomePod's OS. That's when I noticed the scenes that I had set up before and disappeared, appeared again. These scenes even appeared in the Eve HomeKit app where they never have before (or at least I didn't go looking for them there).
I then opened the Home app on my iPad (where I had not updated the OS yet). The scenes could not be seen. I then updated the iPad's OS. The scenes that had reappeared on my iPhone have now also appeared on my iPad's Home app.
This morning, one of the wake up scenes involving the HomePod playing a radio station started.
Happy Days? We'll see!