H friends, I thought some of you might benefit from this post, and that I might benefit from your responses. I've seen nothing on this, yet it's something that's been observed by my myself and a couple of my 'minions.' ;>) Thanks to Roberto Sartori, we have a handle on the apparent cause. Have you ever ended up with an all-black/0.00-value master flat from ImgInt, BPP, or WBPP? What we've seen are good looking calibrated flats that integrate into a bad, black master, thus shutting down the calibration of light frames.
If you've selected Large-Scale Pixel Rejection on either of the scripts' flats tab, or in ImgInt to help eliminate stars in your sky flats, this is likely the cause. Interestingly, if 'Optimize dark frames' is not selected, this seems to bypass the issue, though I've yet to understand why. When both Optimize and LSPR are selected, master darks, particularly, luminance tend to fail (at least in our tests), and adjusting the Optimization threshold/window doesn't seem to reduce the amount of rejection. Thanks Juan, et. al!
