This shows a problem I was having in the switch from Pixinsight 1.8.8.12 to 1.8.9-1. With my camera (Starlight Xpress SXVR-H694 mono), WBPP 2.4.3 apparently defaults to a bottom up FITS orientation rather than top down. My master dark was created using an earlier version of WBPP, which must have used top down, so the integrated result (right) wasn't working out correctly. Switching WBPP 2.4.3 to top down solved the problem.