I just thought I’d post this 'cos it has caused me a bit of pain today so hopefully it might be useful for others.
In a nutshell, if you revert back to UE4 Occlusion after using Steam Audio Occlusion, it appears that you MUST delete any occlusion phonons attached to the sound cue in question. Not just clear it, but actually delete the array element in the ‘Occlusion Plug In Settings’ found under ‘Attenuation Plugin Settings’ when you scroll down to the bottom of the sound details panel.
Even if you select ‘Built-In Occlusion’ in Platform settings, AND disable the Steam Audio plug in, UE4 native Occlusion will not work if there is still a remnant of an Occlusion phonon hanging around.
I would have thought that selecting the Built-In Occlusion in platform settings would be enough to over-ride Steam Audio and initiate native Occlusion but this appears not to be the case.
@dan.reynolds - tagging you in this to make sure you’re aware of the issue.