My Zoom app just opened on its own and started a meeting! Why?

So I was just sitting on my phone with my computer screen idle. I was surprised when my screen suddenly changed with the Zoom app opening and starting a meeting.

I was the only person in the meeting, but I didn't have anything planned, and my app has never done this before. 

I noticed that an update was available. Could this have triggered the opening of a meeting? This is weird. 

Anyone know what's going on or experienced this?