Well, given the JEDEC timing values of all the DIMMs, that all have the same part number, DIMMs 1 and 2 match timings, and DIMMs 3 and 4 match timings.
But the JEDEC and XMP timings of DIMMs 1 and 2 do not match the JEDEC and XMP timings of DIMMs 3 and 4! Also, the Max Bandwidth specs of 1 and 2 does not match the Max Bandwidth spec of 3 and 4.
So there are several possibilities here.
If this was a matched set of four DIMMs, all in one package, then G.SKILL packaged them wrong.
If this is two packages of two matched DIMMs, then G.SKILL has changed the specs of this memory between the time you bought the first set of two, and the second set of two.
If you bought them at the same time, you received two different versions of the same part number.
Your board is faithfully running those DIMMs with the different timing information programmed into them, which is interesting, I've never seen that happen. I assume since they are in different channels, each channel can operate at different speeds independently. If you mixed those DIMMs, one of each set in each channel, they would probably run at the lower speed, but might run at the higher speed if you were lucky.
How did you get these identical yet different DIMMs?