Problem with poudriere after updating to FreeBSD 12

[Carmel NY]

Every time I run poudriere, it emits this error message:

Installed packages to be
REINSTALLED: pkg-1.10.5_5 [poudriere] (ABI changed: 'freebsd:12:x86:64' ->
'freebsd:1 1:x86:64')

I rebuild "pkg" sans poudriere, and it worked fine, UNTIL I attempted to use
poudriere again. Poudriere also insists on making the same change to any
other program I attempt to build if I built it without poudriere.

So, I guess what I want to know is why is this error happening and how do I
correct it? I wanted to completely empty the repository but I don't know how
to do that safely. Other than that, how do I force poudriere to do a complete
rebuild of all the installed ports on this system using the correct
information?

-- 
Carmel