I was getting a 'burnt taste' on my Davide this morning, similar to what you describe, right after installing a new atomizer.
I found that I had not been careful enough setting things up -- the atomizer wasn't seated tighly enough into the base of the Davide, while the Davide was screwed too tightly onto my mod (I need to use a wrench to remove it).
After making a couple quick adjustments, everything was fine.
Regards
Glenn