As per the Data dump page, one of the Limitations with the usage of scripts in Forms is that "script may not work if the form is over 32 KB. You can limit the size of your forms by using multiple smaller forms, and by including character/word limits on your text fields".

This limit is very small and the Form does not load or return all he values in "JSON" data when we use Forms with a huge number of fields (800+ dropdown values in Forms).

It would be great if this value is increased so custom scripts can read and parse the Forms with huge number of values.