Again, you're not wrong, but none of those things are insurmountable. If the team is really so stressed it cannot spend 30 minutes, over the many year of the existence of that bug, that seems like a development environment close to hell.
Knowledge loss is precisely my point: there is very little a-priori knowledge needed to solve this, the guy who found the bug proves that.
The maintenance team probably maintains other games as well.
Then you add in the knowledge loss through the churning of developers and over time the organization forgets how things should be.