Speaker groups only play from one device

Hello everyone,

I've encountered a frustrating issue with my speaker setup in the kitchen, which until recently worked in perfect harmony. My setup includes three devices: a kitchen display, a second-generation Google Home Mini, and a Chromecast Audio. I had all three connected to a speaker group aptly named "kitchen group." However, out of the blue, whenever I cast to this group, the audio now randomly plays from just one of the speakers, instead of all three.

I've attempted to resolve this by recreating the group, ensuring all devices are connected to the same 2.4 GHz network and turning off mesh settings for each device within my mesh network, to no avail. Even after factory resetting the Google Home Mini, thinking it might be the culprit, the problem persists.

Has anyone experienced something similar or have any suggestions on what might be going wrong here? Any advice would be greatly appreciated.

Thanks!