LX7 wrong black levels, black/white point hidden parameters?

Please let me know if I should raise github issues for either of the observations below.

#1: Wrong black levels?
I was editing a Panasonic LX7 raw, and found a colour shift when raising exposure.
Without raising exposure:

With raised exposure:

I noticed that the waveform showed different black levels for the channels. I checked in exiftool, and that indicated 128 for all channels, like used in darktable:
Changing the black levels allowed me to fix the colour cast:

#2: Hidden parameter(s)
I created a style using those black points, and applied that to another photo - but the geometry of that picture changed:

It seems that a non-adjustable, hidden parameter, crop right, also changed. I guess this is related to the LX7 being a multi-aspect-ratio camera. I was just wondering why the parameter is hidden.

It turned out to be a regression

Seems more like a 7+ year bug with a magic number no one understands. I wonder if Panasonic fixed the black levels in a newer version of their raw format. The fix worked for several samples I tried. I think I tried the GH5, GH5s, G9 and GX9 in addition to my S5. I didn’t try to push the exposure tho. I’ll have to try older camera samples and retest the others.

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