I have a rule that I use to trigger an Alexa/Echo routine, and the Alexa routine makes an announcement. The rule opens and closes a virtual contact sensor every 15 minutes. When the virtual contact sensor opens, the Alexa routine is triggered. So I get an an Alexa announcement every 15 minutes.
The problem is that the virtual contact sensor is opening and closing every 15 minutes, not once, but twice in quick succession. This triggers the Alexa routine twice. Instead of one Alexa announcement every 15 minutes, I am getting two Alexa announcements every 15 minutes.
The virtual contact sensor is in use only by this one rule.
The rule and the event history of the virtual contact sensor are below.