We suffered one, he was on a two man team. Reviewing his pull requests took at least a day, which were effectively rewrites by the more experienced dev. We eve

We suffered one, he was on a two man team. Reviewing his pull requests took at least a day, which were effectively rewrites by the more experienced dev. We eventually had to let him go, but the technical debt remains. For example, tests that mock everything so that they didn't actually exercise any of the code!