WordPress MU

Using wp 2.5.1 and cannot update right now.

Does anyone experienced this issue? user_login get modified for unknown reasons by the addition of a space character, therefore the user cannot login until I log in to phpmyadmin and update it manually.

So, do you have this issue on 2.5.1 or after you upgrade to 2.7?

On 2.5.1

And ALL users logins have space? Where - in the beginning, in the end?

Not all, once in a while may happen an (1) user may have this space at the end:

before:
"john.smith"

after:
"john.smith "

So he emails me "hey I cant login to the dashboard"

I log into phpmyadmin, remove that space and all is back to normal. Maybe is a plugin that is causing this, or some core bug, I dont know

Check what plugins that are used in blogs where extra space is added for user.