When a page is duplicated, the new page may display 'Block contains unexpected or invalid content.' errors. This occurs because the plugin escapes data during duplication, disrupting the saved settings within Nectarblocks elements. To avoid this, you can use the Duplicate Post plugin or copy your page in Code view and paste it into a new page before switching back to Visual editor mode.
When the CoBlocks plugin is active, it causes JS errors in the editor with Nectarblocks because the plugin globally extends and modifies non-namespaced attributes across all blocks. This overrides some attributes of elements in Nectarblocks, resulting in functionality breaking.
Solution: Disable the plugin when using Nectarblocks.