I have observed it on 10.0-RELEASE-p7 today:
% sysctl -ah | grep vfs.zfs.arc
vfs.zfs.arc_max: 134,217,728
vfs.zfs.arc_min: 517,351,680
vfs.zfs.arc_meta_used: 313,004,120
vfs.zfs.arc_meta_limit: 33,554,432
arc_max is less than arc_min probably because I have added vfs.zfs.arc_max="128M" to...