It does not appear in <site:"domain"> when checking the index. However, it appears in the command cache <cache:"domain">.

It does not appear in <site:"domain"> when checking the index.
However, it appears in the command cache <cache:"domain">.

Three of my posts were listed in the top ranks.
The exposure suddenly dropped, so I checked and confirmed that the post I posted disappeared.

When I checked the index, it was not visible in the 'site:' command, but it appeared in the 'cache:' command.
And when I searched the site on gsc, it shows that it was indexed normally.

This could be due to temporary indexing issues, algorithmic changes, or potential penalties. I recommend reviewing your content for relevance and quality, checking for any technical issues, and re-submitting the URLs for indexing via GSC.

Check for any manual actions or penalties on Google Search Console. If none are found, resubmit the URL for indexing through GSC. Since Google already caches the page, there's a chance of indexing if you submit it again.

cache and site operators function differently and many times the difference can be observed. If you are checking the particular post then you can also try searching with other search operators like allintitle or inurl operators etc. But if due to low quality content or any other reason like safesearch etc. Google is not showing you post in search results then you will need to improve your content.

might be experiencing a temporary indexing issue or a search visibility problem. If the issue persists, submitting a sitemap in GSC might help refresh your site’s indexing.