Your boss knows you are a high performer and you are taking care of bugs and keeping it off his radar so s/he doesn't have to stress about it so he leaves you alone out of respect. He trusts you and knows you are capable and you don't need your hand held, hence your high ratings prior. He may not realize how much time has really passed because things you take up are just done and there isn't a concern and he's focused on other team members who are struggling or need more day to day help. It is possible you are reading into the situation what you fear rather then reality.
I'd suggest you call or send a quick email to your boss that isn't passive aggressive etc. But also do so to protect yourself so it is a fine line. I'd say something like, "Hey Boss, I've solved the last few defects x, y, and z and realized that we hadn't connected recently and wanted to take 5 minutes and just make sure I am doing the priorities you feel are most important." This way if he is building a case against you he'll have to respond in a way you know otherwise his case would become weaker. The fact you let it go on for months is already a weakness, but not beyond fixing. If you ignore, you will leave either by their action or your own and you'll be bitter which can poison your new job search, so do your part and then at least you feel good even if you leave as you'll know you did everything you could.