I have recently activated this mod again, and since then sometimes when using reset all skill points the game crashes.

No other mods since have been activated, but i use a compilation of different mods together, which are:
Settlement capture icon
faster settlement growth 2x
building progression icon 3
easier confederation & vassals
console commands
change starting settlement
and your mod

Since none of those affect directly lords it seems to me it must be your mod.
Note game did not crash specifically for confederated lords but randomly when resetting skills for lords or heroes

When analysing the mdmp file with Windbg i found this:
FAILURE_BUCKET_ID: NULL_CLASS_PTR_READ_c0000005_Warhammer3.exe!Unknown

If you need more information please let me know