Broken breadcrumbs for Email topic

In phpBB, you can send an email for a topic URL (unless the feature is disabled and/or you don't have the permission):

{}

memberlist.php?mode=email&t=XXXXX

Output mail for the recipient:

This email was sent from "phpBB.com" by Big Monstro who thought you may be

interested in the following topic:

Topic subject

You can find it at:

https://www.phpbb.com/community/viewtopic.php?t=XXXXX

However, I've noticed the breadcrumb is utterly broken in the navbar header.

Between Board index and Email topic, one can see the tree of the oldest topic still alive in the database (forum name, parents forums names, and topic subject).

Even more oddly: if you click on the forum links, you are redirected to the (parent) forum of the oldest topic. But if you click on the topic link, you are redirected to the actual topic for which you are sending an email.

On phpBB.com, the header get that exact breadcrumb, regardless the topic:

Board index < phpBB Archives < phpBB2 Forums Archive < 2.0.x Support & Discussion < 2.0.x Support Forum < Removing the "White" from SubSilver, NOT the backg < Email topic

The problem occurs on other phpBB boards, it's not specific to phpBB.com