I was working on a scene with an environment medium (fog) and noticed the cryptomatte pass was changing (getting brighter) as more samples were rendered.
I took the scene into 2019.1.5 and it's not doing this. I'm not sure if this is an intentional change, but its creating some issues in fusion with the cryptomatte script.
If I take an exr from 2020.1.5 into fusion, the cryptomatte picker can only pick "Volume occlusion", which I assume is an automatic material node name you give to environment mediums. I have to manually type in names of the other materials to get a matte.
The 2019.1.5 exr allows me to pick all materials (and "Volume occlusion") using the GUI picker.
I have attached an orbx along with the EXRs exported from 2019 and 2020 modo plugin.
EDIT: I have now included 2 orbx files (1 from the 2020.1.5 plugin and the other from the 2019.1.5 plugin)