Unless you live in a REALLY dry climate, there shouldn't be an issue with a fairly new guitar "drying out" just because there wasn't a working humidifier in the acoustic room. Even the lower end Cordobas should be made with air or kiln dried woods,i.e. there shouldn't be much change in the wood due to moisture content - which leads me to believe there is probably a defect with the guitar itself. I suspect that the tech at your GC is not a classical guitar guy (no offense), and is probably not terribly familiar with the proper set up on a classical guitar anyway - I could be completely wrong here tho. If it were me, I would want to know exactly what the tech means by dried out, and how he thinks that is causing the string buzz - is the neck warped? The top scalloped? Bridge lifting? A new guitar might be the safest bet.
Just my opinion,
Steve T. :cafeine:
"DO or DO NOT; there is no TRY"
~~Yoda (as quoted by Scott Tennant)
Esteve Manuel Adalid 9 C/B