The New Dlc GLAT

So I beat the DLC last night but I’m still a bit confused they say that gyphen is a vault monster…okay but howd it end up on xyfourgos
Theres no vault there so clearly it escaped from one …beacuse vault guardians guard vaults they cant be away from them so…is it just a escaped vault creature is there a vault under the creature was its vault destroyed ?

I’m hoping the guardians just got bored and started making vault monsters.
This is a huge spoiler btw.