On a Joomla 3.9.x site I have a client who has staffed logged into the front-end of their website most of the day mostly using a custom built extension to manage an aspect of their business which I don't think is in play with this issue but worth mentioning for the context.
I have set a Session time of 1 hour in the Global Config and the staff tick the 'Remember Me' box when they log in so in practice they mostly don't have to go through the userid/password process after being an hour away from their browser.
However for staff using the Chrome browser, when they switch to Firefox it does not occur, they can at times be prompted to enter a userid/password within the same hour, sometimes even minutes after their last login for no apparent reason. I haven't been able to find a pattern, a consistent trigger or recreate it on my use of Chrome.
I have tried disabling the preload feature of Google Chrome due to a past problem where Chrome was fetching the Remember Me cookie before it was changed/reset for the next occurrence but it does not appear to have made any difference. As the multiple logins can happen within minutes or within the hour(the session time) it is possibly nothing to do with 'Remember Me' or that fact the 'Remember Me' process doesn't work could point to an issue with a session token or something in that area.
I have some basic error reporting available, as it is a live site, but nothing is appearing in the logs or notifications
It is frustrating for the client and doing my head in as I can see in the User Action log when and how often it is happening and it is very random, some days not happening at all and other days many times an hour. The one thing I can see in the User Action log is that when it happens they are not recorded as being logged out, I see consecutive 'User X Logged In' messages.
Has anyone seem similar symptoms, extra points if you have a solution.