Chromecast Binding - Audio Group weird behavior

I am wondering if anyone else has experienced this weird audio group behavior?

When playing audio with Say/PlaySound, this will play audio at the right volume on the primary device (selected by IP) but then all the other Google Home devices in the same audio group will have the “announcement” chime sound, and then play the audio for 1/4 of a second, and then the remainder of the audio is played at an extremely low volume.

I have checked to see the volume settings are not being tinkered with when playing the audio, and gone to the extreme of deleting the audio group, creating a new one and then setting this up as the default audio sink.

If I play the audio to each device separately, this works fine, just in the audio group it doesn’t play properly on all the speakers.

This only seems to have happened sometime last week, maybe there was an update from Google that broke this?

Has anyone else experienced this? Or it is just me?