Used an AI tool to debug my take-home and now I can't tell if I actually learned the fix or just copied a working answer

Take-home had a gnarly race condition I couldn't find for two hours, pasted the relevant function into an AI tool and it pointed straight at the issue in one try. Fixed it, submitted on time, but now I keep wondering if I actually understand why that fix works or if I just have a fix that works. Going back through it slowly this weekend to make sure it's the former before it comes up in a follow-up interview.