Severe over-correcting / pitching problem

My Hobbyking Go Discover (see photo) has been flying perfectly on the APM2.0 on auto flights after running autotune.

Suddenly it’s developed this issue where it pitches up and down for about 30 seconds as if over-correcting. See short video here

Copy of the PID values on attached screen shot. I guess one or more of the Servo Pitch PID values should be reduced but not sure which one or how much.

Any ideas? Thanks.