So in dead man's chest, tia dalma specifically says that she sold Jack the compass, but in salazars revenge. It's shown the previous captain gives it to jack before he dies. Did the writers forget?

Or more likely they simply didn't care. As a stand alone movie it wasn't that bad. As part of the series however I think pirates 5 was terrible. It seemed slapped together with random characters and plots as if they just wrote a completely separate story then added a few characters from the series to make it a 'pirates of the caribbean' movie