Ha! After a couple of months of e-smoking my 801, I get my Prodigy and my supply of SIX new, genuine DSE801 atomizers. In screws the atty and puff, puff, puff. Later, I go to unscrew it, and it separates at the band! Now I have a dip-able 801! It still works, but I can separate the atomizer from the shell. (And put it back on and vape it, too.)
So I'm guessing that you aren't overfilling - your atomizer is lose in the shell. To test, grasp the base and slightly twist the shell. If they separate, there's your problem. It was not properly swedged on at the factory.