Richterm's Retreat Nordock

Mass Charm is described as an aoe version of Charm Monster*, but is scripted as an aoe Charm Person**.

Not only do the spell description claim it to be an aoe Charm Monster, so do Forgotten Realms wikia do as well.

* Charm Monster do not have any racial constraints.
** Charm Person have a racial constraint to only affect humanoids.

Good catch, I'll look at it and fix it if it is indeed as you say.