I feel like this question was almost answered here but the implementation isn't working for me.
I add a comment activity to Thing A's feed and use the to field to notify specific users about the comment.
If I view the data explorer for Thing A I see the comment. I also see the comment in my user's notification feed.
I then delete Thing A by doing the following:
$feed = $client->feed("thing", "a");
$feed->removeActivity($foreignId, true);
// delete from our app DB
Going back to the data explorer I see that the activity is removed from Thing A's feed but still exists in my user's feed. They both share the same foreign id and from what I understand removing an activity from the origin feed using the foreign id will propagate that removal to all affected feeds. I've verified that the foreign id is correct.
I suppose my question is why is this not removing my activity everywhere? Is there something else I need to be doing to remove the activity from the notification feeds?