I too, was affect by the samba issue. This is 100% reproducible by installing 10531, then upgrading to 10566 (full install).

But you don't need a full reinstall. To fix it, simply delete the file:

 /usr/local/lib/libndr.so.6

Looking at revision r10565 the root path of the installed Samba libraries was changed from /usr/local/lib to /usr/local/lib/samba4.
In the commit an obsolete file list was updated but it doesn't include the file above /usr/local/lib/libndr.so.6.

The directory /usr/local/lib/samba (no 4 at the end) has been moved to /usr/local/lib/samba4/private, so the first one should not exist now.

The following Bash script (don't just paste it to tcsh shell) should help you find other possibly obsolete samba libraries that exist under /usr/local/lib. I still have some, but they are not creating problems at the moment.

#!/usr/bin/env bash

set -e

samba-libs() {
    libs="$(find /usr/local/lib/samba4 -maxdepth 1 -type f)"
    libs="$(sed -r 's/\.[0-9]+$//' <<< "$libs")"
    libs="$(sed -r 's/\/lib\/samba4\//\/lib\//' <<< "$libs")"
    uniq <<< "$libs"
}

found=()

for f in $(samba-libs); do
    shopt -s nullglob
    found+=("${f}"*)
    shopt -u nullglob
done

printf '%s\n' "${found[@]}"