I found a tabula rasa in act 1 instead of act 9

Hi, ggg support team and to whom it may concern

I was in the ledge in act 1 at level 9 using the skills frost bomb,freezing pulse,and arcane surge support on a witch in the flashback event and received a tabula rasa from spiders or skeletons

How is that in any way a bug? Simple Robes can drop in the Twilight Strand and Tabula Rasa has no level requirements.