I have seen the form (but I think not the actual filled out forms for this case), and my memory is that it has a check box to request "jury trial", and a check box to request "bench trial".

As I recall, on the DA's form, they checked the box for "bench trial", while on defendant Trump's form, they didn't check any box at all, which is also technically a valid way to fill out the form, but if a defendant does that, they will usually get a bench trial.

So, through incompetence, Trump's attorney's form was essentially asking for a bench trial, but it wasn't specifically filled out asking for a bench trial.