Currently Unconfirmed/Unreproduced.

On trello at https://trello.com/c/327hZ6nv/

Created attachment 16437
screenshot

(Update with notes from Risker)

This was the process:

• View my notifications onwiki
• follow link in my notifications messages to "Doug Weller created a new topic on Wikipedia talk:Wikiproject Breakfast
• Read (only read!) the threads on the page. No attempt at all to type anything anywhere.
• click "Watchlist" link in the upper right to return to my watchlist
• Get this error message.

(Note from Quiddity)
I've tried again to reproduce, but cannot. :-/

Attached:

(In reply to Quiddity from comment #2)

Created attachment 16437 [details]
screenshot

(Update with notes from Risker)

This was the process:

• View my notifications onwiki
• follow link in my notifications messages to "Doug Weller created a new

topic on Wikipedia talk:Wikiproject Breakfast

• Read (only read!) the threads on the page. No attempt at all to type

anything anywhere.

• click "Watchlist" link in the upper right to return to my watchlist
• Get this error message.

(Note from Quiddity)
I've tried again to reproduce, but cannot. :-/

Just for the record, this was on Windows 7/IE9 using Monobook. After playing around a bit more, it seems to happen only when following a link from Notifications the first time; returning to the page either separately or through notifications does not seem to reproduce.

Attached:

@SBisson is this a duplicate of T95909 or something slightly different?
The original bug report said that it had been reproduced in Firefox as well as IE, so I'm not sure...