vfstab enteries automatically added during live upgrade

i am trying to patch a solaris 10 server using live upgrade.

issue is, when i create a new BE and activate it during reboot the file system that are mounted but doesnt have an entry in vfstab are automatically added in vfstab of new BE.

looks like live upgrade uses df -h output as reference and makes an entry into vfstab file for which entry is missing.

How to avoid this?