-Playing the TEC
I discovered that late in my game i recently colonized a planet and move on to attack another, an enemy arrived right after and i hadnt built any tactical strucures yet, so i built hangars, turrets, etc.
But even before the hangars were built (0-99%)the flak cannons on them were able to fire at enemy ships, and the effect wasnt just a graphical bug, the enemy ships took damage from the flak.