Since the last 2 or 3 weeks, I've been getting logged out of all stackexchange and stackoverflow sites. It started on my iPad and now it's happening on my iMac too. This happens randomly. It just happened a moment ago: I was active in math.stackexchange and when I moved to stackoverflow I had been logged out. I went back to math.stackexchange and saw that I had been logged out there as well.
Is this happening just to me? Can I do something to avoid this annoyance?
BTW, I'm using Safari in all platforms.
EDIT (2015-11-11) This is still happening and it is getting worse in my iPad. Does anyone have a fix?