UCC28061: distortion on ZCDB

Hi, 

I am using UCC28061, when input is lower than 200VAC, everything wroks fine but when input goes up to 220VAC, the distortion begins. 

Following attach is the waveform during the failure, please help me to understand why is this issue happen and how to solve this issue.

thanks for your help.

UCC28061_Waveform.pdf

Please also let me know if further information needed. 

thank you.