Before you send it back or contact Glock, I would try some different ammo. I think there have been some issues with UMC and Glock 19's with the Gen 4. Try some WWB or Federal or anything else and see how it responds.
If you still have some FTE's, then yes, I would contact Glock and let them know about it.
"When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car."