Wing Vibration Issue of VTOL Compound Wing UAV During Rotor Phase

When my UAV is in the rotor phase and hovering, obvious wing vibration is observed, primarily along the roll axis. I’m not certain if this is a structural issue or a parameter-related problem, as I haven’t enabled any filter-related parameters. After reviewing the flight logs, I noticed significant and regular oscillations in the roll rate. The vibration (vibe) values are basically within the allowable range, so I still can’t lock down the root cause. However, I previously replaced the shock absorption plate with a stiffer one—while the oscillations persist, their amplitude has been significantly reduced. Unfortunately, I have limited knowledge in this area and don’t know how to completely eradicate the issue, which has left me extremely frustrated and perplexed.

I did not perform any attitude control inputs; I only pushed the throttle stick.