P0017 "PERMANENT" Code, Won't stay running, Timing chain replaced

Hey all, looking for input as I feel I have hit a wall here.

I'll tell the full story for context. Vehicle in question is a 2010 2.9L Colorado (2wd, auto) with 80 000kms on it.

So I maintain all the vehicles for a few construction companies, got the call for this colorado, stated it wouldn't stay running/would run rough if it did. Engine light on. (Has not had any issues or engine light/ codes prior to this instance). I scan it, code P0017 (Camshaft Position B – Camshaft Position Correlation). I figure it is most likely a sensor but decide to pull the valve cover and see how the chain looks. After having fun with the intake, I get the cover off and notice the chain is excessively loose, can almost pull it off by hand.

So I order the timing chain kit, VVT solenoid, camshaft and crankshaft sensors, spark plugs, and all the necessary seals/gaskets.

The whole job goes rather smoothly (had just done a timing belt on a hyundai santa fe with quadruple overhead cams, royal PITA), with a few things noticed. Engine had some decent buildup throughout, although the oil wasn't dark or dirty. VVT solenoid had a loose screen but it came out with it so accounted for. Tiny bit of metal filings / small flakes on exhaust Camshaft sensor. Also noticed what may have been exhaust leaking from the seam between head and block, cleaned up to monitor for now. Crankshaft had no end play.

After finishing the install and reassembly, and filling it up with fluids, I scanned it once more before firing it up. Even though I had just cleared codes before battery got disconnected, it was still showing P0017, with the "permanent" label beside it. Tried to fire it up and it flashed up instantly, then sputtered out and died. Tried a couple more times with same results. I am positive I put the chain on correctly. Back to the drawing board..

So after a couple hours of research I have learned a few things.
-this is a common issue with this year range of trucks, and does not appear to be limited to the 2.9L engine.
-there is a wide range of things that seem to get rid of the code for good, ranging from just the solenoid or sensor being replaced, to multiple engine flushes, timing chain Jobs, or even whole engine rebuilds / swaps.
-sometimes even the whole engine rebuild / replacement does not fix the problem. (Leads me to wonder if problem is in wiring or ECM, at least sometimes)
-lots of instances need a CASE relearn to be done to the vehicle by the dealer, and only then will the code disappear. (But even this doesn't always fix it, maybe the failed parts need replacing before CASE, and had not been in those instances)
-I did notice one or 2 instances where replacing the camshaft actuator itself solved the problem (end of exhaust camshaft). Also heard told that was what gets clogged/gummed up by dirty oil, and doing engine flushes rectify the code for this reason.
-In many cases it does not affect driveability, and can not go away for years with no ill effect.

Consensus - I may need to get it taken to the dealer for a CASE relearn, but before I commit to that, I am going to do an engine flush or 2 (hopefully can run it long enough to be effective), ohm out the crankshaft and camshaft position sensors and turn over the engine to ensure they are sending a signal, pull the vvt solenoid and ensure the actuator is working (put 12v to correct pin), visually inspect the engine bay wiring harness, and check for power at the plug ends if I can find a wiring diagram to do so.

Sorry if the read was long, but I wanted to give as much info as possible in hopes of receiving a well informed answer. Thanks in advance for any input.

Cheers!

-Zach