I don’t know if it’s anything related, but I had a problem with my own FP2, seemed faultless, but battery drained a lot, and I had 80-90% for miscellaneous, sometimes even over 100%. I opened a thread : Process irq/288-wcd9xxx draining battery
I thought as well it might be some app, turned out it wasn’t. The thing is, it seems to be a hardware problem, so it has to be sent for repair (it’s currently out of order). If you didn’t already do it, I recommend you to backup your phone.
But your problem doesn’t really seem to be related with mine, I just wanted to point it out, if ever it could be useful 