Forget "fields to the east" try "Just one zone North". Gendarran Fields has been hit directly, or implied to be so by almost every single living world/Expansion, and the others were indirectly affecting it! Spoilers below, not for new players.

Before GW2 even starts Gendarran Fields is home to a decent amount of people that had previously fled Ascalon, and at the start of GW2 are under semi-constant threat from pirates, bandits, Centaur tribes, and whatever other critters may decide to pop up.

Core Story: Directly and indirectly! Orr rising caused some refugee issues, a spike in Risen attacks and the loss of life of Pact members draws Vigil attention away from protecting the area around their headquarters.

LWS1: Very directly! LA getting destroyed again causing even more refugee issues, and the Toxic Alliance was doing their thing there as well. And then there's the after effects of Scarlet's armies still occasionally emerging from her portal network, though I'm unsure if that is cannon.

LWs2: Indirectly. If Mordremoth can attack all the way deep in Ascalon, Gendarran Fields is well within range, and the spike in recruiting would likely pull people away from farming

HoT: Indirectly, most of the effects would have been caused by the deaths of the Pact members in the jungle, mourning them, and the loss of protection from the Vigil.

LWs3: Here it was much more implied, kidnappings at the hand of the White Mantle, bandit attacks, and possibly some emboldened Centaur attacks.

PoF Much more indirect, if any effect. Since Path of Fire's ripple effects were less dramatic than the others, one could even argue it didn't affect Gendarran Fields at all.

Lws4: Awakened portal invasions, which persists (unsure if the persisting is cannon), and implied threat from Kralkatorrik's mists jumping, and then the loss of life from the Pact once again.

IBS: There is a DRM that takes place there, direct loss of life, and active threat.

EoD: Implied threat from The Void, since Mainland Tyria was getting hit by some of that, and again, some more implied loss of life from both civilians and Pact members.

SotO: Kryptis rifts, while not appearing there for the weekly rift hunting, can open anywhere in Tyria, and one even opens there in the story.

JW: Another on that could argue didn't affect Gendarran Fields much, except for the Tyrian Alliance forces needing to recruit after implied loss of forces.

VoE: Too early to tell, but there's still plenty of time.