If the MAF were the issue BOTH banks would show an error. The most probable cause is a tiny exhaust leak on the driver's side, somewhere ahead of the front 02 sensor. A tiny pinpoint leak will allow air leaks into the exhaust which will skew readings and trip the code. Other causes can be a vacuum leak on that side or an injector not firing for whatever reason. But 99% of the time it's an exhaust leak.
Don