I have Bridge version 9.1.0.338 and ACR version 11.4.0.273 on a MAC Pro early 2009.
I have several shots in *.NEF format (36Mpixel), and I open them in ACR, using Adobe Bridge. Then, within ACR, I click on "save image" and input export settings reported in screenshot attached to this post. I export 8 files, and for two of them I obtain a pixelated result (attached here). The point is that if I export first from NEF to JPG, setting only the file size at 1.5Mb, and then reopen the jpg with ACR and input the same strict settings as attached here, I DON'T obtain a pixelated result. And when using strict export settings at first, the requested file size of 150Kb is not respected, because I obtain about 250Kb. I can provide the guilty NEF files, but not here on the forum. Thank you.