I have the latest version of the plugin (3.5.4). I have settings to send a weekly update and every subscriber is receiving 2 emails. The log shows that the update is being sent twice with exactly the same time stamps on both send actions. I only have 12 subscribers, but this is annoying and actually caused one subscriber to cancel in an attempt to eliminate the duplicates. I've read through the other threads and it appears that this problem was addressed and fixed back in 2014. It is still there for me. Let me know if there is any additional information you require. I manually triggered an email through setting and it only sent a single email.