Hi Camille,
I’m sorry you’re experiencing this issue after your BoldGrid Post and Page Builder update.
You mentioned you first noticed this error after your most recent Post and Page Builder update. Is your WordPress core, as well as your theme up to date as well? It could be a version conflict of some sort preventing this.
Could you send us a link to your website here in the thread? We’d like to take a look at your site structure using our browser tools to see if anything stands out.
I hope this helps. We look forward to hearing from you if you need further assistance!