My recent update to Swaggle,
introducing some monitoring and reliablity features, has already paid off. It alerted me to a bug I introduced a couple months ago regarding invitations to private groups.
When you invite someone to a private group, it should "pre-authorize" that person to join, so that when they send in the ".join group" message, they are automatically added. Instead, Swaggle has been going back to the group's owner and asking for permission a second time.
This has been fixed. I apologize for the inconvenience, and encourage you to let me know if you see behaviors like this that don't make sense.