When I use my paired home Pods in Airplay 2 only one works at a time.

The amazing thing is that both home pods are in the same room, and it is a small room, and every other song they hand off to one another when I set the playlist from my Mac. The Black one plays the first song, the white one the second. This does not happen when I ask Siri to play something from Music whilst I sit in the room and make requests, it is the stereo effect then.

I looked for some settings and found nothing to adjust. They are paired beautifully as long as I ask the question directly to them, but from my Mac upstairs, I get one or the other speaker.