Finally, the user also jokes that the entire thing could be a conspiracy in which the producers goofed and are now doing what they can to sweep the entire thing under the rug.
A deeper explanation the user adds is that Will and Jazz could have actually been friends for years, and Jazz would visit Will in Philadelphia.
One reason could be that the producers just thought it would be a fun thing to add in the opening.
The Reddit user mentions several possibilities as for why this could be the case.