After I installed Google Messages and turned on RCS (with the option to send as text if it can't send as RCS), Person A, who downloaded the update to her iPhone, was able to see my message, but Person B couldn't see it.
Then I sent a message to both of them in a group chat, and neither could see it. Then I sent it to Person A alone, and she got it (but not the group chat).
I turned off RCS and sent another message to Person A. She hasn't replied, so she probably didn't receive it.
Then I sent a message to both of them in a group chat, and neither could see it. Then I sent it to Person A alone, and she got it (but not the group chat).
I turned off RCS and sent another message to Person A. She hasn't replied, so she probably didn't receive it.