I had lots of scenes when I first noticed the issue. As my scenes had got messy over time I was already going to delete them all and start fresh.
After creating the first 2
Living Room Lights
Living Room Power
I checked that they showed up and cloned and tweaked them for the modes.
Now I cannot see 'Living Room Lights'.
I can work around this. Just thought it was worth reporting.
Update
I have found entering the scene editing nothing and clicking done gets it to show up.
As a datapoint I had cloned the scene a number of times and deleted one of the clones. Though on doing this as a test it did not seem to recreate the issue.
It does not, only clicking done on the missing scene works.
Its the renaming of the clone that causes the issue so there would still be an extra step after renaming.
The cloned/renamed theme shows up fine.
It's the original that has the issue once the clone had been renamed, and reopening the original and clicking done does solve the issue. Clicking done on the cloned/renamed scene has no effect on the missing original scene.