Cisco AnyConnect (VPN) connection always forgets username
Solution 1:
The bug still exists in gnome's network manager but there is a workaround for this from RedHat folks. https://bugzilla.redhat.com/show_bug.cgi?id=1332491#c24
nmcli con mod VPNNAME vpn.secrets 'form:main:username=USERNAME','save_passwords=yes'
replace the VPNNAME with the name you have given to your vpn in network manager And replace the username with the username of your vpn.
Solution 2:
It is a bug of gnome's network manager. It has been reported here and here, so the only solution is to wait until a fix is available or to contribute to fix the bug.