The usekernelcache=no flag isn't fool proof... I think. Just got the no entry again. Although I was trying to install a PCIE raid card and that might have tripped it up. Usually was able to get the drive booting again just by repairing permissions and rebuilding kext cache. Only after reinstalling the NVME kext in S/L/E and L/E I was finally able to boot the PCIE SSD again in addition to repairing permissions and rebuilding kext cache. I've rebooted and powered off over 10 times and it has booted off the PCIE SSD each time with no additional issues.
I'm a hack so I just keep swinging till **** works or breaks. Not sure if everything I did is required or not, just outlining my steps in hopes that it can help others.
Just ordered the Intel 750 PCIE drive so will give that a go once it gets in.