To date (May 2016), I have only calibrated two epochs for polarization. Both are from 2007. I have not invested much time in understanding the issues with the other epochs yet. My main effort is focused on the high sensitivity recent epochs, but they are suffering from lack of point calibrators, possible issues with 3C279 as a calibrator, frequency dependent instrumental polarzation characteristics, possible software issues, and lack of my time.
The images I have show interesting structure with E vectors wrapped around the back side of the core, and pointing along the jet on the jet side, including showing the wide opening angle (assuming that Faraday rotation and other effects are not confusing the issue). Once the current data paper is out, I will be trying to improve the polarization calibration.
The first image is from 2007 Jan. 07. The gray scale shows the total intensity image. The lines show the electric vector polarization vectors.
The second image is from 2007 May 10.