Bug in the_author_posts_link()?

When I use “the_author_posts_link()” there seems to be added a “h” to the end of the the authorname in the title tag.
When I mouse over the link to the author, it looks like this “Posts by user1h“, “Posts by nickh” etc.

The link is working fine though, it’s just the displaying of the link that’s weird.

I didn’t use “the_author_posts_link()” in the past so I don’t know if this could be a bug in 2.1.
Any ideas?

This is the actual output:
<a href="https://wp.class.lan/?author=2" title="Posts by classh">class</a>