Changed my air filter, third time I do this but this is the first time I notice this rear clamp.....
You really have to make sure the filter is well seated on to the air intake in order to get the clamp to clip...

 

If you don't have that attached properly, it'll come loose and you'll get a vaccum leak and it'll misfire. Ask me how I know.

 

How do you know? I can't see how it creates a vacuum leak. its just running with a bit of air bypassing the filter. A vacuum leak would be after the throttle valve. You can run the engine without a filter even.
But I'm always open to learning new things!

 

Your logic is correct however when accelerating hard on the highway with a loose air box its possible that more air than is expected moves through the MAF and throttle body.