It loads a simulation file, creates a compound cut_region (1e4 K < T < 1e6 K), and applies it to a slice plot. The resulting image is banded, as you can see by the attached plots. Am I missing something, or is this a problem related to yt?
FYI, I get the same behavior when I use a projection plot or only one of the conditionals (e.g. T < 1e6 K). I've tried both the stock 3.3.1 version, as well as the self-contained development version that I installed earlier this afternoon using install_script.sh. Let me know if any other info is useful.