CCleaner is logging me out of all the websites in Firefox (v57.0.2) even though I have it setup not to.
These are the only options that I have checked.
Didn't you have the same problem back in 2014?
It was a winapp2 issue back then, so it's probably the same again.
bingo @nukecad, all the *'s to the right of the FF entries are a give-away. (plus the overwhelming number of entries!)
Configure Cookies to Keep and see if that helps.