This seems to happen because Discourse Meta - The Official Support Forum for Discourse actually goes to https://meta.discourse.org/u/user/preferences/ and then to https://meta.discourse.org/u/user/preferences/account.
You can see in the go back history the initial page and the https://meta.discourse.org/u/user/preferences/ page.
If you go directly to https://meta.discourse.org/u/user/preferences/account the error doesn’t happen.
To fix it I think the url https://meta.discourse.org/u/user/preferences/ shouldn’t go to history when you access (only https://meta.discourse.org/u/user/preferences/account).
This doesn’t happen when paste the url the browser.
In my case:
The problem happens: https://meta.discourse.org/u/lucasbasquerotto/preferences/
The problem doesn’t happen: https://meta.discourse.org/u/lucasbasquerotto/preferences/account/