Is the brush on my M97xE defective?FAQ #4681
The brush bristles are indeed cut an an angle. Looking at the cartridge from the front, the bristles on the left are longer by design. To work properly, only a small section of the brush needs to contact the record groove.
As a test, play a record without cleaning it first. If the brush is working properly, it will have collected a small "ball" of dust by the end of the first side.