If it was from day one, I would say that it was low on freon as well. If it does on both then I would think that there is factory defect on the temp probe. Highly unlikely that both would have low charge amounts.... but crazier things happen every day.
Question, when looking up from where the filter is, there isnt any foam or cardboard or insulation blocking the coils is there?
I would check for a blockage first and inspect under the outer cover for anything abnormal. Or if your fairly close to your dealer, take it to them, heck you got a warranty, might as well use it
MillerTime- Future Sabre Handler!!