Another hour, another question – AD integration

I know this isn't probably specific to instaDMG, but it may since it's happening on the images I created using it, but not the images created the 'old' way. We deployed the image to a few systems and everything seemed to work fine. I can sign in with my AD account and everything seems to work. However, when i try to sign in as the end users ID, they can't login. They can sign in to their web-based email, they can sign on to a PC, they can sign on to a mac with an previous build on it (even one they never signed into before). Reset the PWs, not locked out or disabled, etc. Just get the shaking screen when they try to sign in. So I have another IT staff member sign in that never signed on to the box... they get right in - so it's hitting AD. If I sign in, remove the system from the domain, reboot, add back to the domain, reboot, THEN the user can sign in like normal, but until I do that, NOTHING I do seems to work (reboots, password resets, even tried taking it out for a lobster dinner)... The DomJoin is not scripted, it's being handled by casper, same as it has been since we deployed it 2 years ago...