Programming skills are directly correlated to programmer ability to debug, I will go as far stating; programming is not about writing code, but in ability to find bugs and figure out how to resolve them.
I've always found it easier to debug code I wrote, mostly because I find it the easier to read the code I wrote, since I understand the author's intent.
But as the programmer finds bugs and corrects them, they are simultaneously generating more, accurate data for training. So over time this should theoretically improve