Logged In User Name not collected on Form Submit

Hi Guys, I've run into a bit of a problem as I use Gravity forms to collect online tests for a Yoga school. Test's are only available to logged in students and for some reason, for about half of the submitted tests, I didn't receive a User name. Only the IP. This is pretty crippling as we can't determine which test results belong to which students. I've searched the forums and found the solution may have been addressed with the most recent version of gravity forms as is posted in these two forums posts..http://www.gravityhelp.com/forums/topic/form-not-collecting-logged-in-user-data and http://www.gravityhelp.com/forums/topic/auto-population-stopped-working-in-331.

I've upgraded to the latest version and I really hope this seems to fix it, but from now on I think we'll be including a username field within each test for extra security.

Is there any way I can get this information back? Is it possible I could track down the user name in the database somehow? match ip's or something? You're help would be uber appreciated!

Thanks!

p.s. Also, I don't think this seemed to be an issue with WP 3.3.1 or more recent versions not working correctly with GF's as some form submits happened on the same day, some have user names others are missing. So a recent upgrade to WP doesn't seem responsible unless it's a very erratic and intermittent issue...

I'm running Wordpress 3.4.1 with the latest version of Gravity Forms (as of this moment) but GF was only updated today, where as when the forms were submitted it was running an older version which was probably released in February 2012. Until this point, it has been running smoothly, but we had let our GF account expire. Great product! Just need a little support now and again ;-)

I'm using a Membership plugin which limits form pages to only logged in users, so they are the only ones who could have access to the forms. The 'Require User to be logged in' was not checked on the form settings, although the former membership plugins would not let non-logged in users access that content.

The access to this form is locked up for only logged in users so I can't provide a URL, but here's a screenshot of one of the troublesome entries.

I would assume that the issue was addressed in this latest release of GF's which we are now running, but I'm asking more for the help to see if we can somehow track down those Usernames..
Let me know if the URL for the form page is a must for further troubleshooting and just send an email where I can send credentials to access the site.