Preonic BT connection issues on ChromeOS

[obra]

(Reported by krow on discord)

BT with my Lenovo Duet 5 Chrmebook. The first few attempts, I was able to use FUN+1 to connect successfully while on the Bluetooth screen. But, the device didn't switch to desktop mode and keystrokes weren't registering. After a brief period, the Bluetooth screen showed the Preonic as disconnected again. I tried a few times with the same behavior.

Then, I was trying again and started hitting keystrokes right after the initial connection. That seems to have completed the connection. The system switched to desktop mode and the keyboard is recognized. It also reconnects after power cycling the keyboard.

I've been trying to repro the initial problems I had, but I haven't got it to recur. I'll report back if I get it to happen again.

OK, I have a repro case working now.
Forget any existing Bluetooth connection to the Preonic and power-cycle the keyboard.
Go to the connect new device screen in settings on the Duet Chromebook.
Hit FUN+1 on the keyboard. PREONIC #1 will appear.
Select PREONIC and wait without touching any keys. The system says it is connected but after about 30 seconds the keyboard is disconnected. It shows up on the "Previously connected devices list" but it won't reconnect if you hit FUN+1 or power-cycle the keyboard.
To try again, you need to forget that device and start over.
If instead, you hit a number of keys when it first connects, the first few won't register, but then the keyboard connects, the system goes to desktop mode. It also successfully reconnects if the keyboard is power cycled.

[obra]

Chromebook: version 132.0.6834.190