2014 chevy 2500 6.0 negative stft

Hey folks, had a wild day on Friday and now after creating this post I think I know where im gonna start next but would like some other ideas just in case I hit yet another dead end.
another tech pulled this truck in, 2014 2500hd with 6.0, customer stated he had b2s2 o2 codes and misfire. Tech found only codes for b1s1 heater and b1s2 low voltage and p0300. He tossed a b1s1 o2 in and called it good, we had to move the truck the next day and it was not running very good off start up, super sluggish and missing bad. I hooked up and had the p0300 and b1s2 low volt code. Watching live data I found short term fuel trim was cutting way back -20 -25? And thats when the misfire started and theyre all on b1 so cyl 1 3 5 and 7, when it goes into open loop engine runs fine. I watched b1s1 and b2s1 readings and b2 looks fine and fuel trims are single digits, b1 is super slow to start reading almost like the heater is out if it, the down stream on b1 turns on before the upstream does, my voltage for b1s1 however will go as high as 1200mV and only goes as low as 450mv, once warmed up and running it'll flat line at 450mv and our fuel trims will go positive until it bumps up to 600mv then go full negative again until it hits 450 or 400 again. B1s2 is not coming up past 400mv if I remember right that is reading relatively low. Pulled purge line and all the other O2s go full lean under 100mv besides b1s1 which will come down to maybe 300mv if that. Spraying alternative fuel source in intake the others will flat line around 900 950mv where as b1s1 will come up to 1200mv. Very odd to see a O2 going that high so I figured we had a bias voltage entering the circuit, key on engine off our signal wire has 2v bias just like b2, with it running I have about .1v on the ground just like b2, our heater is consuming the same amps as b2, service writer mentioned the other tech stated the new O2 did not look like the factory and there was some doubt, it was a Bosch sensor but we ended uo throwing a ntk in it just to confirm we werent getting a stray voltage from the heater circuit from the sensor. After the O2 was replaced again truck started and ran fine, took it down the road and all was good. Customer wanted us to look into another code further (ebcm loosing com to ecm) and while I was working on that I had the truck running on the lift and that's when it started running rough again and throwing the same codes as before.... ok. Went back through my testing and im still getting the same readings as before, b1s1 reads 1200mv, slow to respond and wont go under 450mv. My next step was to go through and do a injector balance test thinking maybe we got a injector or two not sealing. Other then that idk what else it could possible be, truck runs down the road good, no exhuast leaks upstream of sensors from what I can hear and see and wot test O2s respond fine and truck has no lack of power. I bounced the idea off of AI just to see what that would say and it also brought up possible plugged cat and intake runner fualt? It did mention leaking injectors but idk about the plugged cat and intake runner, as far as I know this truck doesnt have the extra intake flaps and if it was a plugged cat you'd think we would have other codes and runability issues and if the cat was broken down then the down stream should be very active but its not so im thinking it's gotta be a leaking injector on b1 but would like some others input.

Now thinking about this further im honestly thinking the NTK sensor is also not good and one from the dealer should be installed, maybe I'll swap b2 with b1 and see what Happens. If I did have a actual rich running condition like b1s1 is saying then b1s2 should also be confirming that but it is not. I didnt pay very close attention to my down streams but I do remember we did have a code for low voltage on sensor 2 and when the upstream is fixed at 400mv the downstream is pretty low maybe 100 or so mv I now its reading low enough to throw a fault code for that and now doing some reading on other forums it sounds like these trucks dont like aftermarket O2s? I know Chryslers were really sensitive when it came to O2s I didnt know later gms were as well, anyone have insight on that?

Hey Jake! I think you're absolutely right to suspect the replacement bank one upstream sensor.

I know Chryslers were really sensitive when it came to O2s I didnt know later gms were as well, anyone have insight on that?

It's a very similar issue, for sure. From what I understand, it comes down to the internal resistance of the O2 sensor.

GM moved away from the good ol' 450 mV bias on the signal circuit and started using a bias on the signal AND the ground circuit. Service info gives you an idea of what to expect on both:

lemon-manuals.la/Chevrolet/2014/Silverad...%2FSystem%20Testing/

If the internal resistance of the sensor isn't correct, then the sensor will never work correctly with the provided bias voltages. Hence, the sensor signal sticks high (like you saw), and you get a false rich. The parts catalog will insist (insert aftermarket part number here) will work, but they don't.

Move them if you want that extra 110% confidence, but I think you're ready for an OE sensor.

  I agree with Tyler, I just had a similar GM truck with 4 new Bosch sensors with crazy trims, running like trash. 4 OEM sensors fixed it.
I bench tested the Bosch sensors with power and ground on the heater circuit and introduced butane from a lighter. They work, but as you noticed the construction is different, they don't sample the exhaust in the same way. 

thanks for service info Tyler! I was searching alldata and couldn't really find much on there, didn't think about logging into direct hit I'm sure I could've gotten more info there maybe but I was home all weekend thinking about this and it was bothering me.
Thanks Noah for the heads up on bosch sensor's. IMO I thought NTK and Bosch were pretty well respected brands. The last couple months we've been getting nothing but %!$@# parts even from the OEM's, think I'm not gonna have any hair left by winter here.
I'll tell the writer to get me a OEM sensor and see where that takes us, thank you!