Um yeah, a little unusual it is. That would be to release a Comet Lake-S processor so shortly before the new 11th Gen processor release. But it's listed at Intel, the SKU would be a Core i9 10900KS.

If you can remember it, back in 2019 you will have seen a Core i9 9900KS SKU released next to the 9900K, the KS version had a PL2 boost of 5 GHz on all cores. So the main benefit was that all-sore boost on basically what is a highly binned processors series.

Now the interesting part, for Comet lake there is a 10900KS ... listed. Yep, Comet Lake with the same 10 cores and 20 threads. What makes all this a bit weird is that Rocket Lake is to be released next month, and the Cypress Cove cores offering a higher IPC, so the current information indicates that Core i9 10900K could/would be faster than the Core i9 11900K in a multi-threaded test. Perhaps that will be the main selling point for this as yet undisclosed Core i9 10900KS. Mind you that the listing does not necessarily presume that Intel will actually release the chip. 

Intel is listing a new Comet Lake-S processor, Core i9 10900KS