The soul trapping effects in Halldir's Staff and Bloodthorm,
dunHalldirEnchSoulTrapFFAimedArea and
dunHagsEndSoulTrapFFContact, are using the (obsolete?) Soul Trap archtype instead of the Script one, and do not check for the NoSoultrap keyword
In Halldir's case due to having the "No Area" flag, that actually prevents it from affecting actors in its stated area of 15 feet like the calm effect does, it can only soul trap in direct hits.