Apparently there is something in the build setup on beefy18 (and, by implication, the other package builders) that has become stale and must be upgraded.
In the latest build, I am starting to see numerous cases of:
make: "/usr/share/mk/bsd.opts.mk" line 110: "NO_WERROR is defined, but deprecated. Please use MK_WERROR=no instead."
which of course the processonelog.sh knows nothing about, and thus reports "???".
This is due to https://cgit.freebsd.org/src/commit/?id=7fa2f2a62f04f095e1e27ad55aa22a8f59b1df8f