I would inform you that Magisk doesn't work well.
Usually I build rom with root permissions to have a easy flash, but I notice magisk seems to be installed but it doesn't work well. Sometimes I need to flash over Magisk to have it working, because it stops installing modules.
I have noticed this issue since Miui switched from Nougat to Pie.
In the past I removed magisk (and all modules installed), after I flashed again magisk and each modules... but it's annoyng a lot because you think rom builder works well but it doesn't.
Now it starts working again flashing itself over the existing.
I suggest to analize this issue and fix the problem asap.
Phone: Jason - Xiaomi Mi Note 3