HA Beginner- no luck with presence tracking (but works with a custom template sensor?!)

[julianrendell]

Hi there-
I'm trying to get a fairly basic example to work: make a light turn on/off based on my detected presence.

I have the HA app running on my phone, and I've added it as a presence tracker to my user account.
I've also added the ASUS WRT integration, and added a second presence tracker for my phone. That's also been added to my user account.Both trackers have unique entity ids.

A simple automation that sets a notification triggered by the presence state of these two presence trackers works as expected: the trackers' states flip from "home" to "away" as expected.

I've then added an area ("office"), and set office as the location for a light and a fan.

Then set up a magic areas integration for that area. Magic areas is set to include all the platforms (ie including presence), light and fan groups, and presence hold.

Presence hold works as expected- lights come on when it's on, turn off a minute after hold is cleared.

I guessed that a device has to be assigned to the area that a magic-area is added to for the magic-area to react to it.

Is this interpretation correct?

So I assigned my router based phone device tracker, phone app device, and phone app trackers to the "office" area.

The tracker entities show up in the "office" area and also the connected magic area. They appear to show the correct states.

BUT the magic-area presence never changes no matter how the device trackers' states change.

I then figured out how to make a virtual binary sensor, with presence class. The jinja template checks the two tracker states and returns true if either is in state "home". Added this to "office" and it's state toggles between "home" and "away" as expected.
And the magic area works(!)

What have I mis-understood/mis-configured to break device trackers working in magic-areas?

Thanks in advance!