[Plugin: G-Lock Double Opt-in Manager] G-Lock Double Opt-in Manger sends duplicate emails

I have been using G-Lock to send notifications of new blog posts for several months now. Since I first installed the plugin, it has had a problem of sending duplicate emails when I have it set to automatically send them when new posts are published. It does not do it all of the time, but it does happen frequently. If I set it to manual and send the emails myself, it works as it should. I have looked on these forums and on the G-Lock forums, but I seem to be the only one having this problem.