I occasionally get a warning on mainstream sites like Google, New York Times, Washington Post, Ebay, etc. I think it is a temporary glitch in the handshaking between internet providers. In USA where we change our clocks twice a year for day light savings time, I find it happens quite frequently for a few weeks after a change which makes me think that there might be a timing issue. Two days ago for over an hour I was warned that Google website was a security risk, I have had that warning frequently since our last day light savings time change.
At home my home computer is a laptop. Sometimes if I put the laptop in standby mode (some computer companies call it sleep mode), wait 5 to 10 seconds, turn it back on, no more security glitch. But this does not always fix it, only fixes it about two thirds of the time.
My rule of thumb is to try the standby thing first. Then if that does not do it, do not use a site when I get a security warning just in case it is real. But try again later to see if it is working right again and if it is, continue on as if nothing happened.
