When you need to call down the thunder to deal with those pesky biters, launch a rocket with an ion cannon into orbit and show the bugs who's boss.
NEW +3 technologies: Area Fire and Ion Cannon Mk2
unfortunately, i don't have any time resources free at the moment to take a look at this.
The problem has not yet occurred with me.
workaround: increase the reserved cannons for manual targeting.
Okay, so, it did stop eventually. My guess is turning off the setting applies to Ion Cannons that are ready after it's changed. But turning it on applies to all existing ones as expected.