Smoke? No signal? Distortion? Increased noise? I don't have one and I've never seen the schematic.
I'm totally guessing, but maybe you got lucky. I'd guess that if you'd cooked it, you'd get nothing at all... then again, when the amplifier in a hackrf is damaged, it usuall just turns into something like an attenuator. This is a great opportunity for you to learn more about your RF environment, and about designing experiments.
- does the problem occur with shielded USB cables? Ferrites? Better RF cables?
- does the problem occur with a disconnected antenna? With a terminated input?
- airspy's lower end is 24MHz, spyverter's upper end is 60MHz. How similar does the 24-60MHz range look for actual signals, shifted and unshifted?
- compare your 24-60MHz performance with and without the spyverter connected (but not powered).
- can you test with a different receiver (hackrf, usrp, another spyverter) - maybe those strange signals are actually part of your local environment.
- can you detect the spyverter's LO leakage? Is its frequency stable?
That should be a good start.