One specific example, not sure how helpful this will be… I have completed all the quests in Borean Tundra, Howling Fjord and Dragonblight. Just started Grizzly Hills. This is on a hunter that is already level 80.
After turning in step 47 I started having the repeating errors, and then on picking up and accepting the quest from Mikhail’s Journal (steps 51 and 52) it did stop erroring.