Hi, bear with me with the explanation of the bug. It was tested on 3.11dev+ localhost standalone version.
I have a course - let's call it REF - with start date 3 september 2015 weekly format, in which Unit 1 corresponds to the first week. Every activity created (quiz, workshop, assignment, forum) has restriction dates and due dates and availability dates that are located within that first week, on the year 2015.
Backing up the course without users and restoring it manually to a new course with a different start date rolls all the dates correctly in relation to the new start date.
However, using the CSV course upload to do the same on one or several courses at the same time fails. For example, I created a course with a start date of April 18, 2021 based on the The only dates changed are: start date of the course, and the dates of each week. The restriction dates and due dates and availability dates are stuck in the same 3 september 2015 dates of the REF course. Cron was run, no difference. See all my screenshots and the file used attached.
Therefore, CSV course upload cannot be used to restore courses for new academic terms.