OK, I went back to my notes and found why the new HHA didn't fire.
When you set up a new HHA to change mode and use a motion sensor, it also sets a default time restriction for (wait for it...)
6 AM to 12 PM. Which is noon, not midnight, which I suspect was the intended range.
First time around I changed this from 12:01 AM to 11:59 PM. Or all day except for two minutes around midnight.
I changed the time and now the new one works, so at least that part makes sense.
The undocumented "must change mode" though, is somebody's kludge based on their assumptions about how someone else would use motion sensors. It's a clever kludge and I like it as a solution for some use cases. I just don't want it to be mandatory.
My motion sensors are set up as touchless switches. (I'm quadriparetic.) inside a box on a shelf. Or someplace similar. They don't trigger unless there's an intentional hand wave. So I don't want a mode change and I don't need to be protected from repeated triggers.
And I can code, but I don't want to. Even cut and paste is a pain when you're doing everything by voice.
Yes, motion sensors require careful deployment to get the desired results. But don't cripple the scheduler because you think someone might get themselves in a loop when they first set things up.
Put a warning on the set up wizard if you want. But let the user match device capabilities to use cases.
"All home automation is local." 😊