I own a 7rii and gave been trying to scour my manual and the internet to explain on icon I see on my full display monitor screen. It is a small, thick-walled, grey circle with the letters AC next to it. I cannot for the life of me find an explanation in any of the documentation. I have the monitor, viewfinder set for automatic. This icon appears for a short time and then disappears. If I shift from viewfinder back to monitor, it comes back. If anyone can tell me what this is, I’ll sleep better for the knowing.