HomePod mini +/- volume controls now switch the device to a random radio station

The volume +/- touch controls on top of my HomePod minis recently started making the devices switch to a random radio station, rather than adjusting the volume! This is very frustrating. The problem seems to have started around the time the devices auto-updated to OS 26 or 26.1.

I normally play music from my Mac, and the only time I interact directly with the HomePod minis is to adjust the volume.

I have all Siri voice and touch controls *completely* disabled on both HomePod minis: [from Mac mini M2] > Home.app > Home > [right click each HomePod mini] > Accessory Settings > Siri > Listen for "Hey Siri": [Off]; Touch and Hold for Siri: [disabled]; Light When Using Siri: [disabled]

Despite these settings, pressing volume + or - makes the Siri glowing light come on, and the device switches to a random radio station (I've no idea what music it's playing or where it's coming from).

I tried restarting both HomePod minis, but it hasn't made any difference.

Note that I use a third-party app, Rogue Amoeba's Airfoil, to route audio from my Mac to the HomePods. Why? Because astoundingly, macOS doesn't natively support sending audio to more than device at the same time. Using macOS natively, if I select (say) the kitchen HomePod mini, then sound stops coming out of the main speakers (attached to the Mac via USB); and if I select the main speakers, then sound stops coming out of the HomePod minis. Astonishingly, it's not even possible to send audio to two HomePod minis at the same time using macOS - unless you configure them as a stereo pair, which I don't want because they're in different rooms. Hence I have no choice but to use Airfoil just to get this incredibly basic functionality! Apparently, it hasn't occurred to Apple that you might want to play music in more than one room at the same time.

Airfoil lets me select any combination of devices in different rooms. For example, I can select the main speakers (attached to the Mac via USB) *and* the HomePod mini in the kitchen, but *not* the HomePod mini in the bedroom. With this setup, until recently I could adjust the volume on the HomePod minis directly using their +/- buttons. This worked fine since August 2024. It was only recently in December 2025 that the volume controls on the HomePod minis basically stopped working.

Apparently it's too much to expect that the volume controls should control the volume!