UP3216Q, color calibration not sticking on boot?

I have a pair of UP3216Q monitors connected to an Nvidia card on a Windows 10 machine. I'm using the DUCCS software and an i1 Display Pro Xrite device to color calibrate each monitor.  I calibrated the monitor on the right first, then the monitor on the left. I have successfully calibrated each monitor, as judged by a similar brightness and color of the teal-blue background color after the monitor on the left is calibrated.  The corresponding profile for each monitor is stored in Cal 1 in memory on the displays.  However, upon rebooting the PC, the colors of the left monitor is noticeably brighter than the right monitor.  Prior to rebooting, and just after the DUUCS calibration finished and stored the new profile, the background color of the two monitors were the same in appearance. Upon checking the OSD, I see that Cal 1 is correctly selected. The Windows Color Management panel shows that the newly-created profile files are also correctly selected for each monitor.   What can be causing the left monitor to be brighter than the right monitor after rebooting the machine?