I seen someone say this in another forum, I believe it is because there are so many different memory kits available and may not be 100% compatible, especially on the voltages the XMP sets.
You should enter the VCSSA value manually but it may take a little tweaking, somewhere between 1.0 and 1.3, but closer to 1.1 to 1.2, I set my voltages manually and I believe my 3200mhz Gskill CL14 kit needs 1.12
Every CPU is different