I saw site: command of mine get more result and also get less supplemental. then I found then google starting to send me the traffic again. I was so mad when my site not include on SERP for a long long time. kind of happy.
Congrats . SERP Downgrading happens, but it is always pleasant to see yourself right back up on the top hehe. IT
It may be helpful to check how your site is indexed on diffferent google datacenters - http://yourcache.com