How can the game add something that don't exist in any ESM or ESP like the bearded female Boomer in the mess hall?, she has ID 0015d787 but i have checked every ESM and ESP i am using and there is not such ID in use??

I saw bearded female powder gangers, but those were a conflict between IWS and and some other mod i don't recall, obviously as there are no female powder gangers in unmodified game.

Anyway, i found a Boomer with that id in FalloutNV.esm "BoomerMessCF", that uses record 15D790 as template. That's either a hilarious bug, or something messes with the records.

OK will take a look at that ID, thanks.

EDIT: She has no beard in my FalloutNV.esm?

It's a very typical error, I can replicate it myself in ten seconds.
All you need is turning a bearded male into a female. The facial hair is actually a different setting not related to actual gender, so these oddities occur. Turning male into female also maintains most male characteristics, resulting in an.... unappealing female. That's why some Enclave soldiers in Fo3 look a bit weird - originally half of them were female, even today present in their editor IDs.

@ Pistolero

No that is not it, i have checked every Boomer there is in the game and there is no Male with beard that is set to female and no female that has any beard, but in game i have seen a female with beard...that is the weird thing. Also checked IWS and that mod don't add or edit any Boomer NPC's, so that is not the issue.