L2TP lifetime problem

I have L2TP+IPSec set up, and use it with my mac laptop. What I notice is that when the proposal lifetime elapses, the connection just hangs. What I expect is that IKE will step in and negotiate a new SA. Isn’t this expectation reasonable?

ip ipsec pro pr
Flags: X - disabled, * - default
0 * name=“default” auth-algorithms=sha1
enc-algorithms=3des,aes-128,aes-192,aes-256,blowfish lifetime=30m
pfs-group=none