Yes… no easy way around this. Basically when a field is hidden its never really ‘rendered’ at all and therefore the default value only renders on page load…
Here's an alternative. You could setup maybe another question event to also set a default value or you could setup initial JavaScript to that and if $(Field) is = ‘’ then $(Field) = ‘Your default text’ Since the field is hidden you would want to put that code within the initial JavaScript within a Try/Catch block of JavaScript.
Hope that helps!
Candace