'Always open URL in associated program' not working

[AndyScull]

Specifically, it doesn't work on Nexus mods site - example url: https://www.nexusmods.com/fallout4/mods/21497?tab=files
Didn't check any other protocols 'cause I don't have any other associated with programs.
NXM protocol is associated with mod organizer, enabling checkbox for 'always open these types of links in associated program' does nothing, next download still asks if I want to open it or not.
Slimjet: Version 17.0.7.0 (based on Chromium 63.0.3239.52) (Official Build) (32-bit)
Windows 7 x64
Other browsers (chromium, centbrowser open these links silently)

[mailceedee]

same here confirmed it offers to remember by popping a box up but setting doesnt stick. There is something wrong with this browser and the way it does settings cookies are especially flakey