AI on select fire missile turrets will attempt to fire missiles even if there is not enough power capacity to fire them, the missiles will not fire and the ai will contiously attempt to fire them several times a second.
When an entity is selected, the turret will fire missiles until it does not have enough power to fire anymore. Once this happens the turret will never regen as firing missiles seem to pause power regen.
The only workaround is to select an entity then once power is depleted the entity must be unselected until power is regenerated.