I found this weird thing

Or am i the only one?

Sometimes when I start a new course, I find some skills already at Proficient or Mastered.

This probably happens when there are modules overlapping between the courses.  Some videos and articles are used in multiple courses, and maybe some exercises & tests are too.

Uhhhhh...

Yes. For example I have multiple exercises in Pre-algebra marked proficient from an overlap from doing 8th grade math.

And I haven’t started on Arithmetic yet, but multiple of the units already show the percentage completed.

And also there’s one video, I don’t remember where, which is in two different courses or units.