Widget editors not working after updating to WordPress 4.9

Hi. First let me say thankyou for your plugin. I’m currently using it with the Sydney theme and it’s a great addition. I’m having trouble after updating to WordPress 4.9. Existing pages (from before updating to WordPress 4.9) using rows and widgets display fine on the front end, but I am unable to edit existing widgets or edit newly added widgets. Adding and adjusting rows works fine in the page builder, and I can add the widgets fine, but once I try to edit the added widget the screen displays no content to edit (for example a custom html or image widget) just a blank white screen with the regular “Widget Styles” Attributes/Layout/Design menus over to the right, but no widget content to edit or change.

Strangely, the widget content samples (from previously added custom html widgets) are visible in the page builder, but nothing shows up in the popup after pressing “Edit” on the widgets. I’ve not added any plugins or content since updating to WordPress 4.9. The issue seems entirely between Page Builder and something that has changed in WordPress 4.9. Thanks.