Your buddy isn’t done yet
Your buddy’s card shows “waiting” until their day is closed. It doesn’t mean they didn’t move — most often it means their watch hasn’t sent the data yet.
When it’s decided
A shared day only closes once both of your windows are over. If one of you is in a different time zone, it goes by the later one — otherwise someone in Canada would lose a day they’re still in the middle of.
Nudge
You can send your buddy a nudge, at most once a day. It’s one tap and your buddy gets a notification; nothing else happens on your side, and it doesn’t show them how you’re doing.
When your buddy isn’t done
The shared streak doesn’t grow that day, but your own streak keeps going. They’re two different streaks, and one doesn’t drag the other down.