It seems like a problem coming from SweetDate child theme only.
Check their demo site http://seventhqueen.com/demo/sweetdatewp/members/demo/#my-photos all the photos open on the single page.
var rtmedia_lightbox_enabled = "1"; this value set by rtMedia setting which is correct.
Kindly check with the sweetdate developer team, I hope you will get a quick solution on it.