Sitemaps are being generated with a GMT datestamp. I verified this in the actual xml file and it also displays in the plugin interface after an update. Since I'm GMT-8 (Los Angeles) My sitemaps are being stamped with a future date. I don't recall seeing this issue in the past, and Google seems to have slowed down indexing of my blogs so I'm looking for any possible cause.
I've tried both City and GMT-8 settings in my general time-stamp in WordPress with no result.
PS. I donated! Your plugin is excellent.