Dynamic Form include superfulous fonts

I have a dynamic PDF form that has references to Myriad Pro and Courier fonts. Previously the form also had references to Arial. However, when I save the form and inspect it with PDFGears, it shows that the Arial font remain embedded in the file. However, if I save the form as a static PDF form, the unused fonts are removed. The removed fonts in question were in fragments. What is causing this? Using LiveCycle Designer ES4 11.0.1