how other coders have their course certificates even they haven't finished ALL the lessons in a course?

Question

I viewed some of my friends profiles and I saw that they already have course certificates.

Answer 1

They can purchase the pack and unlock all of them :(

Answer 2

Explanation: This happened to me more than once. I completed a course, got my certificate, and later my completion percentage dropped below 100%.

I found out that Sololearn updated the course after I completed it. I got back to 100% with another certificate after finishing the updates.

Answer 3

Maybe they have a PRO membership. Really !