The remember me checkbox when selected sets the cookie lifetime to "0", which in most browsers means "infinity", but in Internet Explorer and Edge (for whatever reason) it is read as "never".
When the checkbox is not selected the lifetime is set to the forum configuration set in the control panel.
IE/Edge users should not select the box to remember their login.
If you use the search function for "internet explorer" here on
UBBCentral you'll see several reports over the v7 series regarding this, most recently "
UBBCentral Login issue".