I think the writers simply threw out continuity for the sake of making this particular film work how they want. The tale behind the compass changed to suit the story, Will's appearance seems like it was done to make him seem more cursed as Henry's trying to set him free and make it stand out more once Will was freed from the Dutchman.
I was also thinking yesterday, how I felt like there wasn't enough of Jack showing off his full character traits, and I know there were some who felt that too much Jack is what made Strange Tides not go over as well as the original 3, this movie feels like they walked in saying, we need something connected to Will and Elizabeth Turner because everyone loved the movies with them, and we need to dial back on Jack Sparrow because there's such thing as too much. For me, that's the wrong thought process, there wasn't too much Jack in Stranger Tides, in fact, if there wasn't as much as there was, it would have felt worse. The problem is everything without him involved just didn't measure up, and even some of the scenarios he was put in weren't as interesting and exciting as the prior films or now Pirates 5.