Pingback comment data disappears

Hi Kayako, thanks for the report.

The plugin has no code path that deletes, trashes, or modifies existing comments in any way. It only does one thing — on transition_post_status to publish, it scans the post content for internal links and calls wp_insert_comment() to add a new pingback comment if one doesn’t already exist. There is:

No deactivation hook
No uninstall routine
No scheduled task (cron)
No DELETE, wp_delete_comment(), or wp_trash_comment() anywhere in the code

This means that, technically, deactivating or updating the plugin cannot remove pingback comments that were already inserted into your database — those rows stay in wp_comments regardless of the plugin’s state. So whatever you’re seeing as “disappeared” is very likely happening somewhere else in your stack, not in this plugin.

A few things to check, in order of likelihood:

• Check the Comments screen directly (Dashboard → Comments), not just the front end of the post. Also check the Spam and Trash filters there. If the pingbacks are sitting in Spam or Trash, that’s almost certainly Akismet (or another anti-spam plugin): pingback-type comments are a very common target for spam filters, and they can be moved without throwing any visible error.
• Do you have Akismet (or similar) active? If so, try checking its log/history for those specific comments.
• Do you have a database cleanup/optimization plugin installed? Plugins like WP-Optimize, Advanced Database Cleaner, WP-Sweep, or Optimize Database after Deleting Revisions commonly include a “Trackbacks/Pingbacks cleanup” feature that runs a query equivalent to DELETE FROM wp_comments WHERE comment_type = ‘pingback’, sometimes on an automatic schedule (daily/weekly), with no error or notification shown. This matches your symptoms very closely: comments disappearing on their own, with nothing logged. Some all-in-one cache/performance plugins (WP Rocket, LiteSpeed Cache, Perfmatters, etc.) also bundle this kind of database optimization under their advanced settings, so it’s worth checking those too. Could you check your list of active plugins for anything like this, and if found, check whether it has a scheduled cleanup enabled?
• Page/CDN cache — as in the previous thread, if a cached version of the page is being served, newly inserted pingbacks (or ones that were removed by something else) might appear/disappear from the front end independently of what’s actually in the database. Worth purging cache and comparing with the admin Comments screen.

Just to rule it out: when you say “data disappeared,” do you mean comments that were previously visible (in wp-admin → Comments) are now gone from there too, or only that they’re no longer showing on the front end of the post?

If you can confirm what you see in Dashboard → Comments (including the Spam/Trash filters) and your list of active plugins, that will narrow this down quickly. Happy to keep digging once we know whether the rows are actually gone from the database or just not displayed.

Check if both LiteSpeed Cache and Advanced Database Cleaner have a database cleanup option specifically for “Trackbacks/Pingbacks” (any comment with comment_type = ‘pingback’), and that includes the internal pingbacks this plugin creates.

Since you said you only run these cleanups occasionally when there’s too much junk data, the safest habit going forward is: whenever you run a manual cleanup in either plugin, just double-check that the Trackbacks/Pingbacks option is unticked before clicking “Optimize”/”Clean now.”

That’s a much better trade-off than giving up either those plugins or Internal Pingback Comments.