aos3,aos4 and aros versions dind't have that bug.
On morphos-native configopus.module just crashes when you choice Palette, with words "68k exception in task blablab " happens. Via stack trace and objdump i found that crash point out on the begining of _palette_slider_callback() from configopus.module (and then crashes in the L_UpdateGadgetValue from library, which crashes in L_AddObjectList from library as well).
I also make a full-blown debug_log with everything enabled on mos, so maybe some more info will be there (through, i think its all will be irrelevant, as it just that palette_slider_callback() should be called now via something like our REFCALL/REFCALL2 macroses or so):
_palette_slider_callback() are placed in the Modules/config/config_environment_data.c and actual line to worry (imho), its line from environment_colour_slider_taglist: