I had a problem with mine last week whereby it developed 'sag' when fully extended. It basically would compress an inch in any position and have 'squish' rather than sitting solidly at the stopped position. I bled it numerous times then checked the pressure (schraeder valve under seat clamp accessed using a socket) and it showed the recommended 250psi. No success unfortunately so I emailed Fishers warranty dept through their website and they got back to me straight away. They asked me to send it back for inspection via my LBS despite me having bought it from Germany. Still waiting for it back or a replacement at the time of writing.
The moral of this rather long and convoluted story is bleed it, check the pressure and if all else fails, email Fishers Outdoor Leisure and I'm sure they'll sort it. They've always been very good at warranty stuff in my experience (I suppose dealing with SRAM they'd have to be!)
Hope that helps