I've noticed that in some purchased modules that include dynamic lighting, but whose maps were not originally drawn with a VTT i mind, the doors and other such openings aren't wide enough. For example, in the Curse of Strahd module that I purchased here on Roll20, the maps use the same graphics as the ones included with the physical product but with dynamic lighting barriers, lighting and tokens added. However, the openings (doors, etc.) on these maps are usually drawn less than one grid square wide, and when the DL barriers were drawn to match these drawing the gaps are too narrow to allow players to move their tokens through. Because of this I've had to manually alter or re-create the DL barriers for most of this module. I could move the player's token through the doorways for them, but that's annoying to both me and my players and tends to break immersion. I don't really expect a fix for existing modules, but in the future this should be taken into account when converting published material for use on a VTT.