Update Jan 2021: Unfortunately, there are not currently any suppliers that are able to mass produce PCIe 4.0 riser cables/cards to the quality and specifications needed for our products. A lot of the suppliers are currently having bandwidth issues with PCIe 4.0 risers. Given that some new compact cases from some of our competitors that require a riser card also only come with a PCIe 3.0 riser cards, means that this is something that everyone in the PC case business are having the same issues with. More information can be learned here in this Hardware Canucks video: https://www.youtube.com/watch?v=KwfAF5XjXbM&ab_channel=HardwareCanucks
We have heard recent reports that owners of the new PCIe Gen 4 graphics card, are having issues with PCIe Gen 3 riser cards in general. Since the Node 202 riser card, the Flex VRC-25, and the Flex B-20 riser cards are PCIe 3.0. It, unfortunately, is likely to encounter similar issues.
However, some motherboards do let you manually set the PCIe 4.0 slot back to PCIe 3.0, but that is entirely dependent on the motherboard. If your board has this option, it should hopefully correct the compatibility issues you're experiencing with no measurable effect on the performance of any graphics card currently available.
Tech-Tuber Science Studio also mentions this PCIe 4.0 issue with riser cards in one of his more recent video where he tested several different riser cards for potential latency issues: https://youtu.be/QtoagBoelsU?t=79We're are still working to address these issues, but in the meantime, we apologize for the inconvenience and hope that at the very least you found this information helpful.