While using a Dell Poweredge FX2s, I experienced a sudden loss of power and the PCIE stopped working.

Hello, I am running two Dell Poweredge FX2s model servers. 

Recently, I have been forced to watch as the PCIE has become unavailable along with an unexplained reboot.

First, the Dell FX2s CMC not only states that the PCIE is properly installed, it also states that it is healthy.

In the System Board Inlet Ambient Historical Temperature Data in iDRAC, we could observe

what we persumed as a power loss

Secondly, however, in Device Setting on the node, the PCIE 10Gbps NIC was not recognized even though it was installed. 

By accessing the CMC management webpage and performing a CMC reset, I was able to observe that on some nodes, the PCIEs appeared to be working fine, but on 2 out of 4 nodes after the CMC reset, they were recognized, whereas previously all 4 were not. 

As a temporary measure to get away from this completely, I unplugged the entire power cable for a while and then plugged it back in, and when I did, I observed all 4 PCIEs working as intended, so I suspect it's a firmware issue and not a specific hardware issue.

(Both of the 2 units we have are experiencing the same issue)

Initially, I thought it might not be a firmware issue as both the CMC and the Chassis Infrastructure Firmware (CIF) are the latest versions and there have been no recent firmware updates.

https://www.dell.com/support/home/ko-kr/drivers/driversdetails?driverid=cpmvm

I think I found a similar scenario above with the Dell support driver update. 

Has anyone else experienced the same symptoms as me?

I'm trying to prevent the problem from recurring, but I'm not sure what to do.