I've just realised I also own the 4th edition Adventurers League product "Halaster's Lost Apprentice".
I like part of the backstory - a group of adventurers found a new part of the dungeon and were pretty much wiped out by the ward protecting it, but now that the ward is gone the area is wide open for exploration by everybody else. Seems like an idea worth stealing.
The adventure itself is 12 encounters (a mixture of fights and skill challenges), apparently designed to be run in 12 short AL sessions. The maps in the PDF are all black and white, despite the back cover blurb mentioning two full-colour battle maps. Did AL stuff come as physical products originally?