Yesterday Google announced on Twitter that they have deprecated support for social profile markup for knowledge panels. According to Google, you can either claim your knowledge panel or let Google check out without the markup. Here is the screen shot:
You can visit the Google docs about social profile that mentioned at the top in red color text “Social profile markup for Google knowledge panel is deprecated. We now automatically discover social profiles to include in Google knowledge panels. If you’re verified as an official representative, you can suggest a change directly. Learn more at Update your Google knowledge panel.”
I think spammers can take advantage of the markup so Google decided to deprecated with it. See more details at Twitter.