Working from mobile and will upload tune and log later. My 2011 Sierra 6.2, D1SC- goes pig rich into boost, as in breaking .5-1 PSI. Wideband goes to 8.XX to 9.2, and then comes into commanded, and will go pig rich again.
I had the opposite problem before doing the speed density patch and changing supercharger to "fitted" where it was leaning out as I was building boost.