That deffo sounds like there is something very wrong there. RY and mush? No sir.
The first thing I would do is check all the electronics. As Slarti mentioned might be something that was in the guitar or maybe a wiring error when installing the PUs. Those things happen easily and I have made mistakes in that department more times than I care to admit.
Sides that again, what Slarti said.
And on BKPs and mush: I have played riffs and powerchords on the neck PUs of my axes (Mule, Aftermath, Mississippi Queen, Manhattan (!), Supermassive, Crawler) for minutes with rather substancial gain (Tiny Terror gain @ 2 o´clock + overdrive) without noticing. xD Went for over 10-15 minutes on occasions too when I had a rather slight low cut in action too.
There was an apperant difference when changing back to the bridge, but on their own even my necks are less mushy then a lot of stock bridges I have encountered. Though admittadly the necks have a darker voicing in comparison.