The most common problem we see with Ohlins steering dampers is air in the damper. With heavy use air can be dragged in through the seals, collecting in the damper body. Air creates lag in the damper so the bars can move quite a long way before enough damping is generated to slow the movement.
In an accident it is common for the shafts in dampers to bend. Sometimes this is a big noticeable bend, others it's not noticable until the steering damper is stripped. A slight bend will drag and stick in the bushes making the steering heavy.
Regular servicing keeps the damper functioning properly preventing tank slappers. When servicing Ohlins steering dampers we use genuine spae parts and high quality damper fluid.