I just noticed that in v1.32.0.1, when using PBR rendering, semi-transparent HUDs appear opaque.
This is due to a
bug introduced in LL's DRTVWR-596 maintenance viewer.
Here is how to fix it (this is just a shader file to replace): right click on
fullbrightF.glsl and save this file, then copy it to replace the bogus one inside the app_settings/shaders/pbr/class1/deferred/ sub-directory of the v1.32.0.1 installation directory.