If I send an iMessage to my son using his phone number, the new message effects work without issue. If I send an iMessage to him using his email address (still in Messages), they do not work and show the parenthetical text ("Sent with xxxx effect") when he receives the message. When I send it, I see the desired effect. Neither of us have reduce motion or anything of the sort turned on. Note that they are both "blue" iMessage conversations.
I've tried deleting the conversation where it was failing (to his email) and that didn't change anything.
Is there a reason why he would see the effects if I send to his phone number vs. his email address?