Monochrome module in Darktable still shows color?

[David_LaCivita]

I haven’t done a lot of B&W but I’m helping a friend process some wedding photos and she wants some in B&W. I recently profiled and calibrated my laptop using Argyll and am using that profile as my display profile. When I use display profile in darkroom (softproof) and apply the monochrome module my histogram still shows colors:

But when I switch the display profile to sRGB(web safe) my histogram switches to grey scale:

The same happens no matter what method I use to convert to monochrome. Only using channel mixer does my histogram show no color. This has me confused.

Latest stable build running on Ubuntu 17.10.

[sankos]

It’s probably to do with the kind of monitor profile you created. Use a matrix-type, ver. 2 ICC profile, not a LUT-type and not v.4.

[David_LaCivita]

I guess I have to re-re-calibrate. Luckily, my last profile doesn’t create the same behavior and the only difference I can see is Wayland: