Can't map midi to all params (set_taper)

I’ve run into something. @Blit had a nice video in the ‘oooooo’ topic where he/she maps volume and panning to a midi controller. This does not work for me (nothing happens when clicking K3 on the parm in mapping menu). After looking in the code, cross referencing other scripts I can see that it seems connected to params:set_taper. I don’t have enought knowledge in code to know what to do next. The params that can’t be mapped are all missing the dash in the mappings menu. This was missing in @Blit s video aswell but the mapping looked like it worked anyway. Is it a firmware thing or does it have to do with the script?