I'm not really sure where to post this, since it is an issue with the AI.  Regardless, I doubt that it's intentional, and figured you nice people would like to know.

Playing on Doppleganger with 4 hard AIs, open teams, I noticed after capturing one of the players planets (itself taken from another player) that after twenty minutes of owning the planet, the AI still had not destroyed the structures that the previous owner had built, including resource extractors.  This happened in a few instances.  I think the AI simply may too busy with its fleets to deal with these buildings, but here it is really hindering itself.

As a point of interest, the owner of these structures was long dead when I noticed them.  Perhaps structures could decay when their owner is defeated?

Anyways, feel free to move this.