The GFDL model also has it as a very intense storm. It's very possible it's seeing the effect of an Intense Major and it's making it's on steering currents. Often there is a momentum factor with strong Major storms that take longer to move or curve. That's one of the only things I can think of other than it obviously sees a stronger high.

The GFDL would create a massive storm surge scenario that Miami has not seen since the 1926 Great Miami Hurricane.

Despite how reliable it is a model, all the others don't see what it sees.

Emily's track was perfect, she just didn't intensify and stay together if I remember.

What else the GFDL sees I don't know but it's hard to ignore.