But now the value is not normalized. Invalid usernames are kept, but invalid titles are removed (valid titles are normalized).
Can you provide an example?
If the provided user is normalised, we would be providing the unnormalized one, but if it was able to normalize it, it should be able to do that a second time, too.
You can use a lower case username to test the normalization. A invalid username is with <, > or [, ]. Title aswell.
It looks nicer with a normalized username and other special pages also does that.
Platonides, can you have a look at this one again?