The sensitivity of a given pixel is a function of the fraction of its well depth which is filled. Although the full-well depth of the detector is 116,000 electrons (corresponding to ~38000 ADU using a gain of 3.04 electrons/ADU), the detector begins to have a non-linear response at the ~1% level when the well depth is ~16000 ADU (or ~49 000 electrons). It should be noted that the linearity response of the detector was performed for a different gain and with the detector readout electronics tuned differently then they are presently.
Until a new linearity measurement can be performed, users are advised to keep the pixel intensities below ~16000 ADU.
At this time there is no primitive to apply a non-linearity correction in the pipeline.