Progress Bar doesn't update in units, navigation between unit pages

Trying out CoursePress Pro and I can't get past these issues:

(1) the progress bar always shows 0% and '0 of X mandatory elements completed.'
Even though the items are not assessable (I'd prefer they were) and the unit is unchecked for both of the following:
- User needs to answer all mandatory assessments and view all pages in order to access the next unit
- User also needs to pass all mandatory assessments

(2) If in a unit, on say Page 1 of many, you answer say 1 of the 3 questions, then select 'Save Progress and Exit', when you return:
- you are sent to Page 2 (where it thinks you left off). You can't return to the previous question. A message "All questions marked with "* Mandatory" require your input." which is great, but how do I answer the missed questions (or what if I don't want to answer these current page questions yet)? How can I return?
- if you manage to work out a way to get to Page 1 (seems to be sometimes possible sometimes by go back to dashboard and selecting the course again), questions 2 and 3 are blocked from being answered, even though they are mandatory
- further, those empty questions contain an error (when WP error reporting is on):

<b>Notice</b>: Object of class WP_Post could not be converted to int in <b>xxx /wp-content/plugins/coursepress/includes/unit-modules/text_input.php</b> on line <b>117</b>

- The questions already answered can't have the answer changed, as the input is not an input anymore but a div
Limit attempts is unchecked for each of these questions (but they are assessable)

Skipping between pages doesn't work (using the numbered page boxes below each page questions), even though they have a mouse-over hand. How can this be made to work (I want to give people the opporunity to review their answers, or skip a question and come back after the rest are done).

I'm using up-to-date WP, the only plug-ins activated are the CoursePress ones. Theme is the CoursePress theme. I've duplicated and tried on another host server and the issues are the same.