Just to be certain, do you mean November and December of 2015? or 2016? Or even beyond?
Next, I noticed in your System Information that you’re running versions 3.11.x of your Tribe plugins – can you try updating to the most recent versions of all these plugins on your site and see if anything is improved?
The current versions and where to find them for download are as follows:
1. Just to be certain, do you mean November and December of 2015? or 2016? Or even beyond?
2. Can you create a new Recurring Event that has this issue, and then take a screenshot of its recurrence settings and share it with us? You can do this by uploading the screenshot to imgur.com and then sharing a link to that Imgur image here in your response.