Carbon Trek Frames

Has anyone else had problems with Carbon Fuel frames? It would appear that I have had a third frame that has cracked/debonded in seven months, each in different places. It is in the process of being assessed by Trek- is this a common issue or have I just been unlucky?
Each time (so far) the frames have been replaced by Treks excellent lifetime warranty but is very concerning. Before anyone asks I am not that heavy (about 85KG at 6′ 2″)and don’t do big drop offs as I know it is a cross country bike

Yes – on a 9.9 in 2007. One catastrophic bout of chain suck less than 2 months after I got led to delamination of the CF on the chainstay and that was that. Back to Trek, said it was fecked.