If a comment is created on a node that is not part of a Group the 'commons_notifiy_node_created_no_groups' email is sent out, stating that a new Node has been created, when actually a comment on said node was created,
This is quite clearly wrong, because as subsequent comments are created users are continuously notified about a new node, that has been present for some time at that point.
Instead, there should be a 'commons_notifiy_comment_created_no_groups' message which should be used.
I suspect this is just down to a copy/paste error that hasn't been picked up as most people wouldn't use a non-group node with comment enabled in Commons.
Patch coming shortly.