Build: v1.7.1.1 3639 Mode: Survival Mode: Singleplayer SEED-ID: 189761 MODIFIED PLAYFIELDS: No Reproducibility: Always Severity: Minor Type: Global Summary: Not all enemy turrets are being recognized as aim by own turrets Description: Some types of enemy turrets do not trigger counterfire from your turrets. Till now I've seen such behavior only for enemy Sentry guns (maybe only some of). Here is an example - "Snowstorm Defense", I believe you can find same types on "Shipyard", "Resupply stations".
Sentry guns are anti-personnel weapons. They're intentionally set to be ignored by turrets. If they were targetable by turrets that would throw off all player and NPC turrets by having you fire at buried turrets inside the basement levels of POIs instead of the big anti-ship turrets that are trying to shoot your ship. This also applies to your own sentry guns.