Second try's the charm, apparently.
Fallout 4: Far Harbor DLC reissue fixes PS4 performance issues - report
A new report from the tech-minded team states the DLC's frame rate is now back at a solid 30 FPS, as you'd expect. To bring this about, Bethesda has had to dial back volumetric fog - which, to be frank, may come as something of a relief to those who found the effect more annoying than atmospheric. The video above shows off the change.
While Far Harbor is chock a block with fun but many PS4 users found the foggy island nigh unbearable thanks to performance dips as low as 15 FPS. If you're on the North American PSN you can download the fixed Far Harbor DLC for PS4 now.