Confirmed to be an "old django" bug. When doing the same tagging on sandbox, that runs on django 1.0 code, there is no problem. So expect this to go away in the 1.0 upgrade.
Confirmed to be an "old django" bug. When doing the same tagging on sandbox, that runs on django 1.0 code, there is no problem. So expect this to go away in the 1.0 upgrade.