This is a known core issue, see e.g. this ticket. There is work done fixing this issue by a complete rewrite of the importer, but no ETA for it yet.
For now as this is only a Notice you can safely ignore it for the time being.
Related Posts:
- Implementing a CrunchBase.com Clone using WordPress?
- wp.media.view.ImageDetails – Save settings as HTML5 data-* attributes for image
- How to share category taxonomy with custom post type (The Event Calendar plugin)
- Are drop-in plugins a product of design
- How can I make it so the Add New Post page has Visibility set to Private by default?
- Use a plugin to handle custom post types?
- How does WordPress handle MySQL row lock errors?
- What is the best page ordering plugin that works well with WPML? [closed]
- Difference between deactivating, uninstalling, and deleting plugins
- Filter Hook on plugin update
- Generic plugin (de)activation hook?
- Is the WordPress HTTPS Plugin Still Safe To Use? [closed]
- Calling function from within functions.php returns unwanted value
- How to prefix `attachment` permalinks with `attachment`?
- How do I register a stylesheet inside a WordPress widget?
- List users except current user using wp_dropdown_user? [closed]
- Has anyone used require.js for handling plugin scripts?
- Edits to plugin not taking effect
- Multisite Backup Plugin [closed]
- Custom Text Under Navigation Links
- How do I know which plugin uses the most resource?
- WordPress plugin for affiliate referral system
- Make the checkbox meta field checked by default
- adding a new value to a serialized array in WP_option table
- WordPress 5 upgrade: until when is it safe to keep project running in 4.x?
- force customers to add only single item to card per purchase EDD [closed]
- Write to / remove from default .htaccess file from plugin?
- How to obtain page breadcrumb based on menu structure only?
- 404 Error on Activate / Deactivate Plugin
- How to Use Parameters with a Do_Action Function Within PHP Tags
- Landing Page Redirect Chain | http->https->https www
- How do I pass a post ID to the page URL?
- Need to change url paramenter of share product pintrest [closed]
- Classified ad website : which solutions to use? [closed]
- wp_redirect() Error in Custom Plugin
- Bootstrap and Custom CSS in custom plugin are being overwritten by theme
- Loading a purchased jquery plugin in a wordpress theme
- Fullscreen Video/GIF Intro
- Multisite for Multisite?
- Basic function call on init failing
- breadcrumb need to show all pages and subpages
- Widget’s container?
- Is it possible not to load theme on a specific page in wordpress?
- How to change shortcode’s default theme?
- How to accept images at multiple sizes and aspect ratios and display as standardized image size / ratio?
- Plugin: connect to external database without showing password
- wp_insert_post() inside save_post(): force WP to not update global post object?
- WordPress truncate posts question (plugin related)
- Microsoft Word documents to WordPress pages adding paragraph tags
- My plugin does not install correctly if a previous version is still installed
- How to disable Wp-PageNavi at the top of the page
- Why aren’t my Follow Me links working?
- WordPress ping spam issue with Ping services?
- 404 errors when updating options in admin dashboard
- Hook from plugin doesn’t fire up from external PHP script
- Custom User Registration Form not showing
- Drag and drop widget always inserts image
- Slideout submenu in mobile
- What database state changes happen after a post is manually “updated” with no changes?
- Display posts by alphabetical order
- wp_insert_post not inserting post from XML
- Admin Custom Plugin List Files in admin Table
- custom fields not displaying on wordpress site
- Overriding a function in a WordPress plugin
- after logout session not destroy from server/website side
- Website always load twice on start
- How to update a database entry with a wordpress plugin?
- Change Woo Custom Endpoint Titles from a Plugin
- Is there a way to display multiple authors on a post?
- custom sidebar plugin issue
- White blank screen while adding or editing pages in wordpress
- Plugin debugging with errors in activation routine
- one admin for 2 wordpress websites
- DB Sync Media Files extension [closed]
- Disqus comment system – change comments number before “load more” button
- What Are the Advantages of Using an mu-plugin
- Disable default posts (Posts,Pages,Comments and Media) in wp-admin
- W3 Total Cache Can’t Really Detect Things
- how to create or rewrite files in wordpress plugin folder
- Is it right way to create shortcode?
- Storing values in Post Meta vs new tables
- Determine if get_the_image has image on Get the image Plugin
- How to show author’s avatar in the post meta data with plugin `user-avatar`
- Translate Woosidebars plugin strings
- How to add different CSS for galleries
- How do I add php to all links automatically?
- Top Contributors Plugin with Custom Post Type
- WP-Minify 400 errors and open_basedir restriction in effect
- Why my site loads too Slow? [closed]
- Plugin Links to page not working
- plugin how to find code and edit it in a template file?
- how do I solve Installation failed: There has been a critical error on your website
- WooCommerce product prices not showing up correctly [closed]
- Can i have limit posts on a specific category and automatically remove older ones?
- manage_{taxonomy}_custom_column not working
- Why wordpress site is hitting itself
- I want create woocommerec match products columns
- How to be Variables and options must be escaped when echo’d?
- Remove embed url for internal links
- How to force login on wordpress error