With notifications turned of, users still get notified when added to a group

I’m an admin trying to add users to a group silently – I’m using groups as a sort of email list as I onboard users into beta testing.

So first I add them to a “Onboarding” group which has these settings:

  • Group and members can only be seen by Group Owners (me)
  • Only admins can mention or message this group

I’m adding the users by dumping a list in the Add Users flow on the group’s page, with both options unchecked including “Notify Users”.

What’s strange is that after adding them all, I get notifications like `Username accepted your invitation". They seem to show up for a handful of users, maybe 10-15 when adding hundreds of people to the group.

My question is, why are they being notified at all?

It seems at odds with @joe’s comments here:

and @markvanlan’s post here:

Is this a bug or is there some subtlety to the group adding behavior I’m missing? Thanks!