That's fair. We have more room for improvements on catching errors. It does go through a lot of back and forth testing and error handling, but obviously things still slip through. The more difficult ones to test for are the ones where FG doesn't recognize the characters and replaces them with gibberish in-game.
The module actually does have many improvements over the physical books though. For instance, the maps are all scaled up to be usable for play instead of as references. All encounters have the tokens pre-placed on the map and the monster stats are placed in-line instead of requiring you to go look them up in the MM. If you've ever done this yourself, you'll know that it takes a lot of time rescaling the maps just right, making DM and player versions, etc. Pre-linking all the story entries is another long process.