CURRENT: r365325: mounting ZFS within JAIL now fails: /sbin/zfs mount -a: failed

Running a most recent CURRENT (FreeBSD 13.0-CURRENT #1 r365325: Fri Sep  4
11:28:14 CEST 2020 amd64) with JAILS also running CURRENT of the very same
version, one specific jail which is designated to be a poudriere jail with ZFS
filesystems doesn't start after an update today.

The message is:

[...]
cannot mount 'POOL00/ezjail': Insufficient privileges
cannot mount 'POOL00': Insufficient privileges

Prior to the update today, everything worked fine and the jail was able to
mount its pool; "enforce_statfs= "1";" worked so far, I have no clue what is
going wrong here.

Can someone shed some light on this?

Addendum: As mentioned in /usr/src/UPDATING, 20200824, I did not upgrade the
pool.

The host has been rebuild from clean /usr/src/obj and so the jail's image
(using ezjail and /usr/src as the jail's base).

Help is appreciated,

thanks in advance,

kind regards

oh