Evertz Microsystems Software Design Engineer interview questions

First round is HR 15-20mins phone interview Second round is onsite interview with 3 engineer managers Questions are pretty fair and easy. For HR interview, they went through your resume and ask some basic questions. For onsite interview, questions are fair

Got invited to an on-campus interview, which I passed easily (reverse a linked list). Next step was group on-site, which included a tour and then individual interview with a member of their team. For whatever reason he decided to ask me to implement bubble sort. I struggled, not with the code, but because I didn't actually understand how bubble sort worked (who bothers to learn the most inefficient algorithm?). I guess they thought I understood it and simply failed at coding which is why they decided not to extend an offer.