Wow, that's fairly severe damage. It looks like the motor wires got hot enough to desolder from the board. The newer ESCs have heat sinks but they don't have any specific failsafes to avoid something like this. However, I don't think we've seen an ESC get damaged like this when a thruster is jammed. Do you know if the thruster was completely jammed or just had increased resistance?
Being completely jammed would cause the ESC to try to run, but at relatively low current, which shouldn't cause any damage.
Being partially jammed with extra resistance could cause the ESC to run at higher current and could cause damage. I imagine this is what happened.
Can you describe the thruster jam more?