Windows 10: Phone Link can't text into group

I am using Phone Link on a Windows 11 Pro PC connected to Galaxy S23. There is one text group that I created on my phone, and I cannot text into this group from my PC. I can text into other groups. When I text into this one group, it doesn't reach the group. Each time I attempt to text into the group from the PC, on the phone there will be a single text entry with a very long title, like "kruhkttmrqxsk1onft..." as the recipient. The message goes nowhere. I've tried resetting the phone link app on the PC and the phone. No joy.

:)