The statement
push route-gateway 12.5.0.1 255.255.0.0
is invalid: it instructs the client to use as the route-gateway 12.5.0.1/16, which does not make a lot of sense; the route to the 12.5.0.1, which is the VPN server IP, is added already, and you can also not specify a network mask here.
Remove this line and the warning should go away.