enblend misses 1 or 2 images (Hugin 2016.2.0, Enblend 4.2)

[klausmayer]

Does anybody have an idea why Enblend sometimes misses 1 or 2 images and leaves a hole in sphericals?

I find that if I use Numerical Transform to shift yaw, Enblend either picks up the image or loses another 1 or 2 images at a different location.

At times there are no masks in the missing image, other times there may be a small part masked out.

No error messages in the logfile. No warning messages for the missing image. The builtin blender seems to work but I seem to get some miscolouration at some spots.