Generate users "Notice: Undefined property: stdClass::$uid in profile_user_presave() line 218 of modules/profile/profile.module.

Hi guys

I'm joining the testing of devel. I just installed last D7 alpha 5, no other module. I wanted to generate some content/users before testing D7, but generating 50 users gave me this error :

Notice: Undefined property: stdClass::$uid in profile_user_presave()  (line 218 of /Applications/MAMP/htdocs/drupal-7.0-alpha5/modules/profile/profile.module).

50 times (I counted).

Then I created other accounts. No problem. Completely deleted them all. Recreated some (50, then 10). No problem. Then deleted again and created again, without any problem. I can't reproduce the error, and as I'm writing this issue along with the tests, I'm hesitating whether I should post it, but I chose to post it.