An MRI isn't a clear cut test. It is an imaging technique. The images must then be interpreted. There is room for mistakes in this interpretation process.
Obviously, I have no idea if that is happening in this case. But we must admit the possibility, especially if other more rigorous medical evidence is not present.
My lab does MRIs of humans and animals. There's a crazy amount of variability in the structure and function of an allegedly "normal" subject's brain. For example, a good friend has what looks like an extra little bump near the vertex. He's normal enough though, and will probably finish his PhD this year.
The Brain Imaging Center does refer people with weird scans to (clinical) neurologists. They've caught a few things, but the vast majority of those are also "weird, but apparently fine" too.
As an example, here is a NYtimes article about MRIs being misused and misinterpreted in sports medicine: https://www.nytimes.com/2011/10/29/health/mris-often-overuse...
Obviously, I have no idea if that is happening in this case. But we must admit the possibility, especially if other more rigorous medical evidence is not present.