Game opening more than once

So when I click the icon on my desktop to start up Beamng it starts fine. Ill play for a little bit and my game will start getting the occasional lag spike and run slower in general. When I exit out of the game I notice that 1 or even sometimes 2 other instances of the game are running in the background. So my questions are; are other people experiencing this? Why? and would that effect my frame rates and cause lag spikes?

Thanks for the assistance,
Scott