I have an odd issue going on. For 16 months I have had a keyword rank on Page 1 in Google. About 1 month ago it disappeared. The page must have been de-indexed. It didn't show up in any searches I did, including looking only within the site.
I made content updates on the page, re-submited my sitemap.xml file and even got a new link. Nothing seemed to bring the page back. Suddenly, one day the page was back. Two days later it was gone again. Today it back, but yesterday, the page could not be found.
I work at a large company, and our site is crawled daily.
The only change that I can place to all of this is a server change from about a month ago. My network guys set up a load balanced server system. The site exists on two servers. A page request can come from either server regardless of the server the last page came from. Each page request comes from (basically) a random selection of the two copies.
Could this cause canonical issues? I read that Googlebot bases crawling on domain not I.P., but could separate boxes cause this issue?
This is only happening with Google. Rankings and indexing is consistent from Bing and Yahoo. No changes with them.