Recent or current bugs interfering with persistence of package data?

I have a query that calls some package functions, and the functions depend on the persistence of package variables to operate correctly.  I was warned that there is (or was) a bug where flushing shared pool invalidated packages currently in use and thus wiped out the values of package variables.  If this happened, it would cause invalid results to be returned by the query.  Has anyone heard of this bug, or know of any other bugs interfering with the persistence of package data?  Thanks!