1) Create a new course (with the course format "topics"). All other settings should just be the default settings
2) Add a choice activity to section 0 (just enter some text into the fields and save)
3) Edit section 2 (Topic 2)
4) Go to "Restrict access" and click on the "Add restriction" button. The condition should be:
Student must match the following
Actitity completion <Your choice activity> must be marked complete
Notice: <Your choice activity> should be the activity you just created.
5) Click "Save changes" to save the changes
Section 2 will now be marked with a "Restricted" label.
Do step 3, 4 and 5 for section 3 and section 4 as well to add restrictions to those sections.
6) Create a new course
7) Click the cogwheel icon and choose import.
8) Go through all the steps and do a full import from Course 1 (just import with all settings).
The "Restricted" label is now for some reason gone from section 2 (Topic 2) but not from section 3 and 4 (Topic 3 and 4). See screenshot:
Some times restricted labels are missing from other sections as well after the course has been imported.
Everything seems to work fine during course backup and restore. This is only an issue on course imports.
This is a bug in both Moodle 3.5.3+ and 3.4.3+.