I've recently seen a small number of teams create Spikes for defects. That seems strange to me. If you have a good reason for doing this, please let me know.
It should be rare that we’d have a spike to research a defect. Defects almost always have some amount of unknown research and debugging to them. It would seem strange to me to have a SPIKE to debug a problem which would then be fixed under a Defect.
The exception case may be if we want a triage/debugging step where we figure out what’s wrong and estimate the effort to fix before agreeing to fix it. But typically with defects, once you know how to fix it, actually fixing may be faster than all the debugging. By the time you’ve got it debugged, you know exactly how to fix it. I rarely find that approval step necessary these days.
I haven't heard of spiking defects discussed in the agile community so I assume it's generally accepted that this is not a recommended or common practice.