pkg install fails in jail with v 1.8.7

[Thomas Thompson]

Hello,

I've run into an odd problem with pkg v 1.8.7 and jails on a FreeBSD 9.3
server.  I'm getting the same error as described in this thread from the
forums:  https://forums.freebsd.org/threads/56490/ where package installs
fail and report two errors (snipped from jail install logs):

pkg: dup2(rootfd): Invalid argument

pkg: Fail to create /usr: Bad file descriptor

It's not an FS issue as far as I can tell (fsck returns clean), and it goes
away if I lock the pkg version in the ezjail.current file before doing
updates and installing new packages:

pkg lock -y pkg

pkg 1.8.7 works fine on another server, and my google-fu isn't finding
anything obvious.  Any help / pointers here would be greatly appreciated.
For reference / on the server is ufs.

-T.J.