I started a new easy base defence and immediately got swarmed by apocalypse hunters among others. Lost 100 uranium in a furnace. Destroyed all enemies and retried the base defence with another 100 tungsten only to lose it again in the same fashion. Apparantly there was a harvester somewhere nearby, but I couldn’t find it and after failing the misson some enemies despawned while others kept attacking the truck as if the base defence was still active.
Is this a bug or was it always like this? I never played base defences before (and probably never will again unless they fix crafting back) so not sure if clearing the 500m radius area around the base is prerequisite to start the defence.
base defense repairs are always free even if your not in a base defense mission, if enemys are lurking around and damage base or if you damage your base, even traps & red oil cans when shoot just hit that repair button anytime free
Did the Medium base defence mission yesterday and got one of the drills destroyd, so stupid you can’t repair them individual as other building elements during the defence, and there is no waves of attackers with time to repair between either btw. But after the defence mission was done and I repaired from command center, the destroyd drill had it’s resources waiting there anyway?? It was destroyd before mission was complete.
Then the neighborhood started to attack also, as always!
Not only those closest to your base but also the cousins and siblings from the next county.
Most of the times it’s only Runners and Hunters but occasionally a Harvester or Tank want to join the after party too. It’s almost like a second base defence direct after when it happens.
even if your not in a base defense mission, if enemys are lurking around and damage base or if you damage your base, 
anytime free