Android Wear 2.0 has had some growing pains. Many users (including some of us at AP) would rather use version 1.5, due to major changes to how notifications are displayed and other annoyances. And as with any major software update, there have been a few bugs here and there.
One bug affected people using recurring reminders, causing them to be completed without any user interaction. This was initially reported on the official Android Wear Help Forum in early June, with several other people reporting the same problem. Ernest, a Community Manager at Google, has now replied to the thread with the following response:
An update on this, we are aware of this issue and working actively to fix it. It should be fixed soon with an update in the Google app. Thanks for your patience and for providing feedback.
He went on to say that the Time to Leave card, which appears when you need to leave for a calendar event, is related to this bug. Hopefully the fix will come sooner rather than later.