[2020] First fight with a scorch beast (Xbox1X

I'm currently lvl 58 (loving the double xp weekend). I crossed path with the scorchedbeast and decided to fight it. I got it down to a sliver of health left (after it already mutated). After being attacked by it, it dissappeared, I couldn't find it for my first kill.

My question is, is there a set time for a player to beat the scorchedbeast?

Thanks in advance.)