Hello everyone! Michael Breines directed me to this thread today as he noticed he's not the only one reporting this issue, and thought you all might benefit from a status update! So, from our troubleshooting so far we've found out that the Add invites as tentative appointments can cause meeting duplication in Outlook 2016. This doesn't happen all the time, but it is an issue we've seen intermittently and are troubleshooting further. Development believes they have the root cause narrowed down, but will need to continue testing to confirm before they can release a fix build for this unfortunately. Intermittent issues are always the worst!
Disabling the Add invites as tentative appointments can resolve these issues, but introduces problems accepting invites on other third party applications like the Blackberry+ suite. At least in that scenario we have narrowed down the accept issues to a display problem in the Blackberry+ suite. The workaround involves enabling the Add invites as tentative appointments toggle, but this reintroduces the issues outlined above.
We're digging into this further, and hope to have feedback/resolution soon. I will follow up here when we know more as well. Thanks for reading, and have a great rest of your week!
Kyle Kerst
Lead Internal Network/System Administrator
SmarterTools Inc.