I tried creating a new game with only The Sunless Citadel, but it still lagged, not quite as much as the other one, but still too much. The odd thing is that I created a game with Waterdeep: Dragon Heist, and have no issues whatsoever as of yet. I did not have any of the lag for The Sunless Citadel, by the way, this is the game I created titled "Tales From The Yawning Portal" that is having the issues, prior to 8/29/18, and at that time I had all of the "Tales" modules added to the game, and just archived the ones I wasn't using.