Live Preview not showing content, Craft 3 I use the same templates for live preview as for the front end. Until a recent change in Craft 3, they worked fine for live preview, then they stopped showing most fields.

I use a lot of includes to build pages, for example, I send the id of an entry to a separate template to display a Matrix field. I just pass entry.id.
According to Brandon, in live preview, you can no longer use entry.id, you have to use entry.sourceId to get the current draft.

https://github.com/craftcms/cms/issues/5087#issuecomment-541243645