Thanks for reaching out and thanks for using Venetian WordPress theme with BoldGrid Post and Page Builder!
No worries, you aren’t doing anything wrong. I’m not sure if the WordPress update may have had something to do with pencil icon not opening the customizer. One thing you could try is navigating from your dashboard to Customize<<Menus<<Social Media and that should bring up the same menu options.
I hope this helps. Please let us know if this works for you.