System crashes after adding 2nd SSD to Precision 5510

I have a Dell Precision 5510 that came preinstalled with a 1TB PCIe nvm hard drive.  I added a second SSD to the empty SATA drive bay.

All kinds of problems ensued.  Initially, I had two major issues: (1) All windows updates failed after I added the drive, and (2) the SSD drive would periodically disappear, always after large data transfers but if used for small data transfers it would not seem to have any issues.  Disabling the SATA drive in BOS did not fix the first issue (Windows Updates/Reset failing).

I tried every windows update repair trick I know, and even tried resetting the windows install and reinstalling from the Windows Media Update download, but all fixes failed with no error message.  Restting, and reinstalling even failed!

Eventually, I decided to to a bare metal Windows 10 installation.  This too failed!?  I found a Dell tech note online related to a desktop unit, which stated that there was an incompatibility between the NVMe driver and the SATA driver, and suggested that installation would be successful if I disabled the SATA drive temporarily for the install, and then re-enable it after install is complete.  This seems to have worked.

However, while the bare metal install worked to allow a reinstallation (only after deleting my factory installed Windows), and it seems to have fixed the windows update problem, I still have the problem with the drive disappearing (the SATA drive) when there are large data transfers (50-100GB seems to be the magic number).  In addition, there is now a new problem - when the SATA drive disappears, the system crashes with a BOD (error messages are not consistent, I have seem a "memory" issue as well as "unknown" exception).  

It seems like there is some incompatibility, but not sure where to look to fix this.  Ideas?