I am guessing the track prep was lacking. The last drag event I went to, the track was not prepared. My friends GT500 was running 12.6 to 12.8 with M&H racemasters. 2010 Camaros were only running low 14s.

 

The normal trap speeds (116) with bad ET's tell me it was track prep, and that's exactly what the OP mentioned. Conversely, if trap speeds were really low for everyone, that would indicate bad weather conditions (high DA from low barometer, high temps, and/or high humidity).