UHD8000 (v1.3.05): Roon Ready zone intermittently enumerates as 2-channel after boot, fixed 7.1 EDID

Device: Zidoo UHD8000, firmware v1.3.45 (Not 1.3.05)
Roon: 2.73 build 1696, Core on Linux, no Roon DSP
Chain: UHD8000 main HDMI out > HDFury Vrroom (FW 0.63) input 2 > audio out to Marantz AV20
Zidoo HDMI audio setting: Auto

Problem:
After some boots, Roon sees the UHD8000 as a 2-channel device only. Multichannel FLAC (4.0, 5.1) is then downmixed or not offered as multichannel. On other boots the zone enumerates correctly as 7.1 and multichannel playback is perfect. It happens on most boots and even drops back to 2channel after some period of inactivity.

What I have ruled out:
- EDID content. The Vrroom presents a fixed custom EDID on this input (table 44, 4K60-420 12bit BT2020 7.1, which is LPCM 7.1 192 kHz 24-bit). It does not change with the state of the AVR or display.
- Hot-plug instability. HTPC mode is ON for this Vrroom input, so HPD to the Zidoo is held steady.
- The rest of the chain. Playing multichannel ISOs from the Zidoo's own player has always produced multichannel output through the same path.

What recovers it without a reboot:
- Switching the HDMI output setting on the Zidoo and switching it back.
- Changing the AV20 to another input and back to the Zidoo.
After either sometimes both steps, Roon shows the zone as 7.1 again.

My reading:
The Roon Ready service appears to read the HDMI audio capabilities once at startup, sometimes before the HDMI audio device is ready, and then keeps the 2-channel result. It does not query again until the HDMI output is re-initialized.

Request:
Please have the Roon Ready service query the HDMI audio capabilities again on a hot-plug event and at the start of playback, not only at startup. I can supply logs. Tell me which ones you need and how to capture them.