Why does 2 identical memory sticks show differently?

[ruggb]

I have four 8GB memory cards installed. Two pairs. Why does Row: 2 show different than the identical one in Row: 3?
Shouldn't it be Row: 2 - [P0 CHANNEL A/DIMM 1] - 8 GB PC4-28700 DDR4 SDRAM Corsair CMK16GX4M2D3600C1B
What happened to the [P0 CHANNEL A/DIMM 1] -
Is it a HWINFO bug or something else?

 

[Martin]

HWiNFO can properly assign a module to memory slot on mainboard (e.g. [P0 CHANNEL A/DIMM 1]) reliably only for modules that contain a valid serial number.

 

[ruggb]

The first pair are Crucial and they show a serial number.
Neither of the Corsair modules show a serial number but Row: 3 is OK, so why isn't Row: 2 correct? OR why isn't Row: 3 show the same as Row: 2?
Why does the position of the module depend on reading a serial number - it is a physical slot? That doesn't make sense.

 

[Martin]

Because slot naming and location is mainboard specific and the BIOS doesn't provide enough details to properly link an SPD address to a specific slot. Unless all modules have a serial number.

 

[ruggb]

Yet it is properly labeling the module that is in the row?
I would think the name of that row would be based on the row # not the module name or s/n?
So why would it label it correctly for an identical module in Row: 3?
Strange!