Index Page Lost in Yahoo Site:Example.com Search - Then Self Corrected

Anyone Else Notice this Anomaly?

[Jaid]

A while back, I had an issue on a site of ours where doing a site:mydomain.com search yielded our index page of the site at about position 100 after most of the other pages. This caused searches for our homepage to be very diluted i.e. we werent showing up in serps even for the most detailed terms about our company.

We did nothing to be penalized in any way, and contacted Y! about the issue, who sent the obligatory 'your site does not comply' email to us.
Since we had done nothing wrong, we did not send a replay email back and instead waited. Within about a month the issue had stopped and our index page was now the first listing in the site: search.

I recently have had this issue now with another site.
Has anyone here experienced the same phenomenon. No pages have been deindexed, all of the pages in our site are listed.

Any thoughts would be appreciated.

Jaid