If I had that reading on my 06, I would just use that as an excuse to put on my Progressive rear spring now and add fluid and fully bleed the line. You need to remove the adjuster from the shock to fully bleed the line as it needs as much fluid it can get before you split the line. You will bleed it back to "0" when you put it all back together. Since I have adjustment starting at 2, I can wait until I wear out the stock spring somewhere around 50K.
A good service department will replace that shock assembly under warranty. They do not service them as Honda has classed the entire preload and adjuster as “non-serviceable”. They are either having them assembled in a fluid bath and do not get the piston set properly or they are using a vacuum prior to fluid fill and assembly. In any case, they are just not getting the fluid filled properly.
I refilled my ’02 (hit 9 before adjusting) and the end results would compress just getting to 1. There was no sound change in the adjuster at all. It had two sounds, going up with a load on the motor and going down with no load.