Same issue still exists with latest patch, enter the cave and quest automatically updates.
https://forums.obsidian.net/topic/82933-202-a-farmers-plight-not-completable-px1-related/
https://forums.obsidian.net/topic/82528-cannot-talk-to-korgrak-for-farmers-plight/
https://forums.obsidian.net/topic/82397-a-farmers-plight-quest-bugged/