Does the second round of reviewing process typically take a longer time than first round? I would like to firstly state that I do understand the essence of the reviewing process in scientific publications.

I have submitted my article to a material-science relating journal. The first round of revision was very fast; it took less than 10 days. One of two referees suggested a minor revision while the other asked for a moderate amount of questions.

Currently, it takes 3 weeks after two reviewers agreed to make the second round of reviewing.

Thus, is it common that the second (and later) reviewing process require more time as long as the first one?

P.S. Editor privately informed that they are same referees.
In my experience, it is usually the other way around.  The first round of reviews typically takes longer, because the reviewers are new to the paper and first reading it and forming their opinions.  In the second round, they are more likely to be simply looking at differences and seeing whether they agree with your adjustments and replies to their comments.

There is, however, a lot of noise in the process, because in most cases the main amount of time is not spent in reviewing per se, but rather in waiting for the reviewers to make time in their schedules to review.  It differs from journal to journal of course, but sounds to me like in your first round of review you got unusually lucky with the reviewers' schedules and things went very fast, and the second round of review is taking a more "normal" length of time.