@grandma2pkmh, I noticed this, too and I think it's important for posters to be aware so I want to repeat what I posted on another thread.
I can log out, leave the site, and later return and see that I'm logged in. It's happening with my iPad and my Mac, no matter which browser I use (I've tried several).
The only way to assure that I'm completely logged out is to
1 -- sign out
and then
2 -- immediately delete browser cookies/history/cache/website data.
This is a problem. It is not good. When we log out of a website we need to know our session was completely, totally terminated, and at the moment this isn't always happening.
Few things reveal your intellect and your generosity of spirit—the parallel powers of your heart and mind—better than how you give feedback.~Maria Popova