A critical warning related to meta tags module??

Hello
Just to share something that happened to my cuentos site some weeks ago. I was configuring metatags to include geourl info (previously was it was only including description, abstract and keywords fields). When I checked the geourl field to be included, then automatically DC.title tag was added to my all pages (although I didn't notice until some time ago).
The problem was that this was considered by Google as a duplicated tittle issue, and my pages were so heavily penalized that it was almost impossible to find my site in Google, even for keyworks that were very, very closely related to my site, that previously were #1 or #2. It took me about a week to discover what had happened to my site's rankings (webmaster tools was very helpful with this, although it took some time to report the "duplicate title" cue). Once I removed geourl field, DC.tittle disappeared and good rankings returned after another week. At least, I learned something very valuable, don' do that ever again!

Has anyone of you experience those kind of problems with DC.tittle tags? is it supposed Google to consider them as a duplicated title tag, and penalize them?