You can talk to the NPC who normally raids the base and start the event via diagloue, but the event will never start. She’ll even attack the Firebase with her companions, but then she’ll proceed to just run around in circles inside of it with them. Forever trying to capture it (and never succeeding) If you talk to her while she’s in the Firebase she’ll act like she already captured it while dredge respawn over and over inside of it.
I’m pretty sure this event being broken is creating a brick wall which is not allowing connecting events to start.