Not sure if anyone has run into this...might be a bug. I even see it happening on the demo page for the great validate plug in.
I am using the code to capture all of the validation messages in one container. When you enter nothing and hit submit you get the messages just fine, but if you correct one of them and hit resubmit it will allow the page to submit even though there are still required fields. Go to the top demo here: http://jquery.bassistance.de/validate/demo/errorcontainer-demo.html hit submit, then enter 3 chars in the top field...hit submit again. It will submit the form. Anyone else run into this?

