c2g in Gimp 2.10.12 not performing as in 2.8

GEGL’s c2g function in Gimp 2.10.12 performs very differently as compared to v2.8. the outcome is much brighter, and the deep blacks are gone that were so helpful to simulate a film-based appearance. i played with the settings for radius, samples and iterations but nothing comes close to the former appearance. clicking the ‘shadow’ button didn’t improve the result. so, the current stage of c2g is pretty useless for me - unless i do something substantially wrong. i use 16bit tiff files converted from Leica M10-D DNG files.

i didn’t try yet the command line version for c2g in case that’s an option with 2.10 - but i anyway never got that to behave properly in 2.8 either…