One thing that is not made clear in the article, is that there is a separate reflog for HEAD, and separate reflogs for individual branches.
HEAD reflog logs changes such as “checkout: moving from next to main”. Branch reflog logs changes such as “branch: Created from HEAD” (first entry in branch reflog). Most are common to both (i.e. git logs both to HEAD reflog and the reflog of currently checked out branch).
Note that you can examine branch reflog to find where branch was forked from (1st image), or tell Git to examine it for you with
git rebase --fork-point