Duplicate content in WP 5.4

Since upgrading to WordPress 5.4, the content I've created in sections is being duplicated into one single classic WordPress block above the sections area. This is happening on every page and no matter what i do it always appears when logged in to wp-admin. Interestingly it doesn't show up on the live site and if you look at Chrome dev tools there is no trace of it either. If i change the content in the classic block it does retain it but doesn't effect the actual page. I'm happy to fire over some screen shots if that will help you out. It's not affecting my development but it would be nice to get it fixed.