I was suffering from the same issue and after hours of research and stress, I found a solution. You’re right about Siteorigin being the issue. What you’ll want to do is download WP Rollback. Once you’ve downloaded it, you should see a button titled “Rollback” next to each plugin on your plugins page. Go to your SiteOrigin plugin and roll it back to the previous version. It’s that easy. There are 2 Siteorigin plugins that I had and I’m assuming you have them as well. I rolled back both of them. The plugin names are below:
Page Builder By SiteOrigin
Siteorigin Widget Bundle
I hope this helps you because this resolved the issue for me. In fact, I created this account just to help you out.
Have a nice day!
Also, check out my website, thanks!