When using the 'email topic' under any topic, it shows up at the top the first topic of the board. 

The topic actually emailed is the correct one, but on the menu it says the first topic of the board.

Like that.

I used that topic for a sample https://www.phpbb.com/community/viewtopic.php?t=2644771

And this is how it looks in the breadcrumbs.

I tested on a few boards, with same results.