Its not an over rated bulb, it happened a lot on the pre-lci models. BMW had a firmware update for the FRM to lower the voltage sent to the bulb, but I can't remember what the SIB was.
If thats the right side tail light, I have a perfectly good one that I will sell you for $125 shipped. I have the left side too, but it has a burn mark and crack like yours, just without the piece missing
