As @azzAz says that wire is scorched a bit near the 1x PCIe connector. It looks like it overheated. Probably not enough power to the riser or a surge.
USB pcie risers run 1x yellow power wire (12v) and 1x red wire (5v) into the Molex connector. That cheap ass ribbon cable you bought has a single power and no ground wires. Heck, it probably cost you as much as a good PCIe USB riser would.
I sell PCIe risers so take my advice with a grain of salt, but don't you think it's weird that your Molex connector usually has 4 wires running into it but you only have 1 in your ribbon riser?
Aye, I never bought ribbon risers, I got USB risers and paid import fees before retailers had them, ebay, wtvr, they came up even cheaper nonetheless, the idea of a piece of electrical tape and some exposed bell wire, idk it put me off, + the benchmarks in certain tasks that the ribbons would bottleneck in different implementations, not sure how true that is, probably more towards gaming. I don't even know what the parts on the USB risers do, they might not even do anything XD, the capacitors etc. but they look generally more polished and safer for high temp use 24/7 operation. like something that's ok to plug into your computer.
Edit: it does happen even USB risers are rubbish, you get one out of a bundle that is DOA if you get them from a bulk source, untested, etc. or just from a bad supplier, (more components can fail, more room for QC measures to fail) but all in all, from everything i've seen over the years, they're a much better and safer choice.
