Software Occlusion doesn't work on static mesh with multiple materials but 1 masked material?

Alright, so my issue is that the mesh doesn’t get considered as an occluder if it has a masked material of any sort.

A way to fix this is to seperate the mesh into 2 meshes, 1 for masked and other for opaque but this will increase the drawcall count. Is there any other solution?

Mesh with 1 out of 2 masked material


Mesh with 0 out of 2 masked material