During a 90 minute discussion with the support team a couple weeks ago, I actually demonstrated this exact issue multiple times. The team failed to resolve, explain, or provide a release number for the fix. This occurred on my M2 Pro and 12 mini…both with the latest updates. Applies specifically to (and only with) new SMS conversations from the mac. Additionally, it’s clear Apple hasn’t even properly acknowledged the issue or replied to this chain. The failure of Apple support to follow through or provide an adequate response on this is astounding yet quite typical. For now, simply use your phone to start group messages.