I'm having the same issue and I also keep having the discovery guides for how to play the game coming up none stop. It appears to be a glitch with the new update / expansion.
I am having the same issue with the discovery quests in the save with the seasons selector screen with the new pack. I have another save where I didn't get Trashley (? spelling) ask about the discovery quests and I didn't have the issue with the seasons selector screen in that save, though it's quite possible the repeating quests is just a coincidence and it's probably just a separate bug, especially since the repeating discovery quests have continued even after I resolved the season selector screen issue coming up with travel by temporarily disabling the Seasons pack. I've not yet looked to see if the issue with the repeating discovery quests has been reported.
