Hello Luke
Strange enough I have the very same problem. Exactly the same. But with another VFD (Fuling) and another board (Pokeys57CNC) and another Spindle. The VFD settings seem to be correct as I can perfectly operate the Spindle manually. But when I connect to the Board - as you did - I have the same effect as you had.
Therefore: Did you solve it? If yes: how? :-)

And hint is appreciated!