Most often because the comb is not clipped fully home on one side, or the wheel has moved mid-trim — both leave a longer strip that only shows when the two sides are compared.
Four causes, in the order worth checking.
The comb. Push it home until it clicks on both sides. One sitting a fraction proud lifts the blade off the hair along that edge.
The wheel. On a trimmer with forty or more settings, two clicks knocked out of place is invisible until afterwards. A locking wheel removes this failure and both Braun trimmers here have one.
Direction. Trimming with the growth lays hairs flat so they escape and stand up later.
The blade. Hair packed behind the teeth cuts unevenly. Brush it out mid-trim on a long session.
If all four are excluded and it still cuts unevenly, the blade may be worn — on trimmers that is usually the end of the tool rather than a replaceable part.
Last reviewed August 22, 2026