Which browser are you using? I’ve just tested a workaround using Chrome and the ‘Tab Reloader’ extension…
Open a separate tab on the main dashboard page
Set the dashboard tab to reload every 30 seconds (thus keeping the session active)
On the main tab set your uploads running
Ignore any errors as uploads will continue in the background
I set my network speed to 10Mbps to test a slow upload of a big file.
*** this didn’t work once the upload had finished. The browser session timed out and I was logged out as before.