Is this common? Rust around tail light sheet metal

[Aeko]

Howdy everyone! When I started to prep the passenger side tail light on my e36 for rust removal I noticed that it also was affecting the driver's side to a lesser extent. It almost looks like it's rusting from inside the body sealant (visible more on the inside). Has anyone else noticed this being a common issue? I ask because it looks like there's a factory drilled hole that is the ingress point in my case. See below:



Outside. You can see a small black hole where the water was entering:

2018-01-15 16.25.41.jpg

Inside. Note the rust inside the sealant on the left side. Looks the same on the driver's side but the rust where the top of the tail light assembly seals isn't nearly as bad.

2018-01-15 16.25.58.jpg

[enf1945]

was it in an accident ??

[Aeko]

Yes, however it was a hit to the bumper