Hello Sebastian,
many thanks for this beta version. It was well worth waiting for it, the general results are really good, much better in fact than 1.4.22
I use the command line version for testing, with preset Natural. I challenged the new version with an image sequence where 1.4.22 failed. To my surprise the new one failed, too. With almost the same symptoms.
But when I tried to crop the source images to the relevant area before feeding them to 1.x I found something strange - the result was perfect:
Command line was -da -natural -tiff16 in both cases. Both are full resolution crops.
Here the result from full size source images cropped later:
The grey posterized area and the shadows around the leaves are the same like from version 1.4.22
You can download the source images (16 bit TIFFs, 269MB ZIP) for testing from http://www.erik-krause.de/_MG_1271.zip
best regards
Erik