RAM failure in Slot 1 only when RAM is installed in both slots

[aircav]

I have had Kingston Hyperx DDR4 16g installed in both slots for over a year with no issues. 

My problem started with BSOD with stop code: ATTEMPTED _WRITE_TO_READONLY_MEMORY. 

I ran Windows Memory Diagnostic - it reported hardware problems.

I ran HP Hardware diag. - it failed memory fast test showing memory failure in Slot 1.

I swapped RAM sticks & re-ran HP Hardware diag. - it failed memory fast test again, still showed memory failure in Slot 1.

I removed Ram from slot 0 (to verify which slot was slot 1) & re-ran HP diagnostic fast test with RAM only in slot 1 (slot 0 empty) - Fast test Passed.

I reinstalled Ram in slot 0 & re-ran HP diagnostic memory fast test with RAM in both slots - failed again showing failure in slot 1.

So slot 1 only fails with RAM in both slots. Both slots have identical RAM sticks (Kingston Hyperx DDR4 16g & HP shows clock speed of 2667MHz for both).

Since the first BSOD, I have been able to work in Windows normally but have had one more random crash with same BSOD, maybe a week or so after the first one.

Not sure where to go from here. Any ideas would be appreciated. 

[Huffer]

HyperX and other similar performance memory has a bad history with HP laptops. If you check the JEDEC settings you will see that the HyperX is running at a lower (actually higher number but slower performance) latency than it could provide. The system will downclock the performance memory to OEM type specs. Usually issues like this crop up immediately. My best guess is there was perhaps a BIOS update or some other subtle change that caused the problem to manifest. It is easier for the system to set timings on a single module than to make timings work on a dual channel setup is why you only get errors when both modules are installed.  

[aircav]

There was a recent bios update. I may try rolling it back. Do you think there may be any settings in bios I could try changing that would help? HP bios is pretty limited, I am not seeing anything that looks promising...

[Huffer]

No there aren't any BIOS settings that adjust memory timing.