Hmmm... Must be Xposed. I have had no issues at all with this kernel and Xposed modules (especially the ones that aren't geared directly for Xperia devices) can be problematic at times. Then again, this kernel hasn't been updated for months now, so to be fair, it could be the kernel.
Nice to hear that you're into kernel development! I too have heard great things about Pabx's Lollipop ROM, so I may have to check it out some time. Sound volume can be boosted with the Aroma Stereo Mod for the XZ (you can catch it usually at the top of all threads in the themes and apps forum). Now, as a lazy perfection-seeking user, I would kill (and I mean
kill) for a kernel that's derived from KMA kernel source code. That combined with Pabx's LP ROM and we may have a reason for all KK users to upgrade and never look back. So, what do you say, buddy?