Bolt Bounce... and firing while loose of the chamber.. or Out of Battery discharge.
Install a 308ish recoil spring.. if you look at the JP 308 carbine recoil spring, you'll see JP even recommends it.
And double check the crimp on those rounds in the picture.. they look a little wide.
And if the crimp is loose, the setback will be easier to happen.... and full insertion into the chamber may not happen.
Also polish your feed ramps, the bullet setback is from the rough feed ramps "grabbing" the bullet , rather then it sliding on the feed ramps.
I run a Tubbs .308 Flatwire , a 7.5oz extended 9x19 "Dead Blow" ( moving weights ) buffer... and keep the chamber clean ( Important !! )