“permalink to this query” on data.stackexchange.com seems to be broken.
Queries in the Data Explorer are followed by a slug that replaces spaces with dashes. For example,
http://data.stackexchange.com/meta/s/208/keystrokes-per-rep-point. However, when you try and switch sites, the URL replaces all of those minus signs with plus signs, a la
http://data.stackexchange.com/gaming/s/208/Keystrokes+per+rep+point. This causes an error when you try to change site for the same query, since apparently it doesn't like positive attitude.