Audio Out - sessionId bug?

From the node-red-dashboard documentation:

Messages coming from the dashboard do have a msg.socketid , and updates like change of tab, notifications, and audio alerts will be directed only to that session. Delete the msg.sessionid to send to all sessions.

First of all, it refers to both msg.socketid and msg.sessionid. Looking at the debug output, msg has only socketid.

But my problem is that although this is honored for notifications, for audio alerts it is not (i.e. audio out is played on all clients).

Is this a bug, or am I missing something?

Version of node-red-dashboard is 2.15.5