Not sure if this is actually worth filing a bug report about, but we were running the 1.8.0-rc4 release. This past Friday I upgraded to the -rc5 release (after the -rc4 package got pulled and was breaking our chef cookbooks). Everything went smoothly, but a handful of DAGs reappeared in the web-server, with a little tooltip note that they aren't in the dag bag but they are in the scheduler DB.
Sure enough, our postgres db shows them as is_active = t. I manually set them back to f and everything seems fine. But still odd behavior, and it happened in both staging & production during the rc4 => rc5 release. Thanks again for all the hard work on 1.8.0! I updated our cookbooks today to pull from pypi now that it is official. - Vijay
