Hi @Abhisek,

Are you still experiencing this issue? Does this happen to be with a read-only reference field? If so, I had this same issue and the following thread had a resolve:
https://www.servicenow.com/community/devops-forum/make-a-field-read-only-but-keep-the-preview-button...

Adding the attribute readonly_clickthrough=true to the field if it is read only may resolve this for you.