I already reported this with 4.13 and Audio SDK 1.1.0 😞
Finally got my new dev rig set up, got UE 4.14.1 running with FMOD 1.08.15 and Oculus Audio SDK 1.1.1 plugins. There are no issues deploying to Android/Gear VR and sound works. However, it doesn't do any spatialization, sound volume of spatialized events is super low and I can hear it equally well across the level. No spatialization is happening as I turn around.
I did not have any issues with UE 4.13, previous FMOD and Audio SDK 1.0.4 plugins. Everything just worked.
Tried Audio SDK 1.1.2 and got the same story - no spatialization 😞
P.S. Also tried 1.0.4 with UE 4.14.1 and FMOD 1.08.15 - same story, no spatialization. I really want to dev for Gear VR (that's why I got new rig, to be able to shorten iteration time when using UE4), but it appears to be an impossible task when audio constantly broken from release to release 😞
In earlier version I would set "Out" as mono and it worked fine. With current setup I had to set "In" as mono, per docs, and "Out" as Auto (not documented anywhere). That did the trick and spatialization worked in FMOD Studio, in the UE Editor and on the device (before, when I had both set to mono spatialization wouldn't even work in the Studio, not even with 3D Panner).
I'm glad you found the solution to your issue. Setting output to mono would break spatialization. The Spatializer is processed in the track as visualized in the FMOD Studio tool, setting the output to mono will downmix the stereo signal, as you noted the same behavior happens with the built in panner. I'm reluctant to add this to our documentation as it is more specific to FMOD than our plugin and I don't want to over complicate the instructions. The default output is automatic so if left unchanged it should work fine. We could add this as a trouble shooting section if we had one, we'll keep it in mind for the future.