I was at work taking a look at my bike and noticed my battery was sagging and even worse was rubbing on my case (scratched it up pretty good, an issue to deal with later). So I take off the battery and notice the mounting tab was broken! It looks like its on the back side of the oil tank if I'm not mistaken?

Is this a common issue? What should I do to fix this?

 

Corrosion caused by leaking/bad battery's will weaken almost any metal structure. I see a lot of rust and corrosion in your pics.
Looks like that area hasn't seen a good cleaning for a long time. If you remove a battery clean and treat the area around it.
Corrosion is a major problem with commercial aircraft and we are always opening areas just to look for small signs of it.

 

I responded to you over on xlf. The battery tray design is poor on our era bikes.

John