I have come accross a bug if you are using acts_as_taggable and acts_as_versioned on the same model. For some reason acts_as_taggable triggers a new version to be stored in the version history. So it stores two identical versions every time. As soon as you turn off the tagging it works.

I have tried to get around the issue by using the method version_condition_met? in the model. I thought it worked but if the fields were null or blank it failed.

I will try a few more things and post the results here.

Hamza