When asking a station to defend, attack or patrol sector, after a while the command seems to drop off the station, and it stops defending itself. You then have to reissue the command.
The station I am testing this with only has fighters, and while the command icon is on the station for one of the 3 above actions it performs as expected. However when the command disappears, and you don't notice it will stop launching fighters to defend or attack and sit there and get pummelled.
Maybe for a station could we issue a permeant command?