Alva not spawning even with 100% incursion on atlas tree.

Title. Basically no matter what I do, Alva won't spawn. I have an atlas tree with 100% chance for alva, but she never actually shows up in maps. I can try using a different tree with no alva chance and using an incursion scarab, but it won't let me activate the map device. I can use other mechanics as normal. I am NOT using Back to basics.