My FX Compatible mode is set to "Normal" since I'm on VanirAOSP. When I was on CM11 based ROMs I couldn't choose the Music Effects so I had to use the compatible mode with MusicFX - like mentioned by you in V4A thread for PowerAmp.
But now with this AOSP based ROM I can select the Music Effects thus no need to use the compatible mode. I think that we can prevent a lot of issues with Normal Fx Compatible mode.
AFAIK your settings are only for CM11 based ROMs (MusicFX activated and compatible mode). On my side I disable MusicFX into PowerAmp and V4A works as expected even with PowerAmp.
Give a try with an AOSP rom and Chaos kernel