I replicated this, however i was using a combination of missile-beams on the shields then beams, missiles and cannons.
While attacking the station it called for 3 - 4 waves of reinforcements but none came. I was able to overheat it and have my way with it.
Moved on to another station and a similar thing was happening till I hit the armor with a cannon, then reinforcements actually did come.
When I went back to base - there was at least one if not two waves of pirates waiting for me. presumably from the now derelict station I was originally attacking.

I had the same issue last night when creating a rail docking on a planet.
I'm not sure if the mechanics are the same for building on a planet vs a station.