Wrong title in the history popup (firefox)

Hello,
in Firefox, the previous page title that appears with a right clic on the “previous page” arrow is overwritten with the current page title.

For instance, if the first page displayed is:
https://meta.discourse.org/
see what the right click on arrow looks like (it is correct):

then going on any topic, such as:

the title of the previous page has been overwritten with the current page title:

Nevertheless, the link is still valid.