Overview of the issue
The SiteOrigin plugin uses a builder field in many of its widgets including the Layout Builder, Accordion, Tabs, and more. Those widgets are not fully compatible yet with WPML. When you try to translate a page containing any of them, that content is not available in the Advanced Translation Editor.
Our developers are working closely with the SiteOrigin team in order to make those widgets compatible. In the meantime, you can use manual translation for those widgets.