On attaching zones and linked images

Recently updated IPS was added to OI and it caused some inconvenience to developers. The most annoying "feature" is caused by publisher check: NGZ first several publishers should be the same as GZ's publishers and their stickiness should match.
OK, I've set the publishers according to this rule, but today was surprised by fact that I can't longer set openindiana.org publisher to be non-sticky in NGZ. I've set openindiana.org publisher to non-sticky in GZ, NGZ, but still IPS complains on "pkg install":

pkg install: Invalid child image publisher configuration.  Child image publisher
configuration must be a superset of the parent image publisher configuration.
Please update the child publisher configuration to match the parent.  If the
child image is a zone this can be done automatically by detaching and
attaching the zone.

The parent image has the following enabled publishers:
    PUBLISHER 0: openindiana.org
    PUBLISHER 1: userland (non-sticky)

The child image has the following enabled publishers:
    PUBLISHER 0: openindiana.org (non-sticky)
    PUBLISHER 1: userland (non-sticky)
    PUBLISHER 2: hipster-encumbered

I've rechecked. Both GZ and NGZ had  openindiana.org publisher set to non-sticky.  I've followed IPS advice - detached and attached zone. And zone attach -u failed with the same error.

OK. Time for black magic. I've unset userland publisher. Set GZ and NGZ publisher list only  to openindiana.org (non-sticky). The same issue - IPS doesn't see that GZ publisher is non-sticky now. So, I concluded that  information about parent image is recorded or cached in some local zone configuration file. Looked at zone's /var/pkg and found /var/pkg/linked/linked_ppubs, which listed [["openindiana.org", true], [userland, false]]. I changed this file to [["openindiana.org", false]] and after that could attach zone.

I think I still doesn't understand as linked images work (or should work), but they are starting annoying me...