Z10 running 10.3 and Nexus 4. Started with this:
Which then turned to this on the Nexus 4:
Edit: The CB10 app doesn't seem to be attaching pictures at the moment, so I'll try to describe.
Nexus 4 sent a hug sticker, Z10 replied with a heart-eyed smiley. Displayed correctly on both phones.
Later, on the Nexus 4, the heart-eyed smiley sent by the Z10 turns into the hug sticker. Doesn't change on the Z10.