Haha no worries - the spring looks like this when it’s installed:

There is a lot of stress on the upper part because the entire weight of the car is resting on the springs. So over the years, cracks can form in the welds that attach the mount to the frame and moisture gets in and rust starts to form without being immediately visible. I just removed the underbody coating to treat the rust spots I could see, but it seems I was too late - it’s already rusted through.