Delete the LUN mapping. Change the initiator's multipathing mode to a desired value and restart the host. Then map the LUN to the host again.
Solaris STMS cannot update disk path management modes promptly.
1. In initial deployment, select a proper initiator multipathing mode before mapping any LUNs to hosts.
2. Do not unnecessarily change initiator's multipathing mode on Solaris hosts. If it is absolutely necessary, restart the host after the changes.