Problem in pitch shaking

Hello,everybody here,there is a problem in my flying wing plane x8:

diydrones.com/forum/topics/probl … e=activity
The plane takes off by the launcher.I have finished the auto tune of the PID.After the taking off in auto mode ,the shake in the pitch shows as follow.Can anybody help analyze the reason.Thanks!

Hi…I have the same issue in my wing, you find the problem??
Regards