Query around form access within a custom pre value source

Hi, I’ve created a custom PreValue source that needs to dynamically populate based on values entered by a user on a previous page of a form.

The method signature on the FieldPreValueSourceType looks as follows:

public override async Task<List> GetPreValuesAsync(Field? field, Form? form)

While inspecting the Form variable during debugging, it seems like the values entered on previous pages of the form are never hydrated.

Is this expected behaviour and if so do you have any workarounds/advice?

Thanks,
Dean