User blog comment:DaNASCAT/Technical Update: April 22, 2015/@comment-11387016-20150423183238/@comment-452-20150424081252

Also, for anyone who doesn't know "purging the page" refers to adding ?action=purge to the end of the url. Although performing a null edit also purges the page.

With this blank page problem, I have also found that just a normal refresh may fix it. (But I haven't experienced any recently, so it may not always.)