could you export your mission to XML file and post it here? I'll check what can be wrong.
Could you give more information with regards to your setup?
OK, I have got your mission. All routes look good. I have checked segments length and speed - it seems that minimum time between shots will be 3s in most routes.
I didn't find any information of minimum triggering interval for your camera, but 3s should work in most cases.
The only idea - please try to change SD cards. May be some problem with write speed here.