etcupdate whines "Failed to build new tree."

This is during the second etcupdate invocation (without the "-p" flag); I
first noticed it today, during the update from:

FreeBSD 15.0-PRERELEASE #320 main-n279987-9764aa1ccad0: Mon Sep  1 11:30:06 UTC 2025     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/GENERIC amd64 1500063 1500063

to:

FreeBSD 15.0-PRERELEASE #321 main-n280001-405cfeef615f: Tue Sep  2 11:03:25 UTC 2025     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/GENERIC amd64 1500063 1500063


The log shows:
...
installing DIRS ROOTDIR
install -N /usr/src/etc  -d -m 0750 -o root  -g wheel  /var/db/s4/etcupdate/etcupdate-ZO4ftQW/root
install -N /usr/src/etc  -C -o root  -g wheel -m 644  /usr/src/bin/sh/dot.shrc /var/db/s4/etcupdate/etcupdate-ZO4ftQW/root/.shrc
install -N /usr/src/etc  -C -o root  -g wheel -m 644  /usr/src/bin/sh/dot.profile /var/db/s4/etcupdate/etcupdate-ZO4ftQW/root/.profile
install -N /usr/src/etc -l mr -o root -g wheel -m 644 ,config /var/db/s4/etcupdate/etcupdate-ZO4ftQW/root/.profile /var/db/s4/etcupdate/etcupdate-ZO4ftQW/.profile
install: target directory `/var/db/s4/etcupdate/etcupdate-ZO4ftQW/.profile' does not exist
usage: install [-bCcpSsUv] [-f flags] [-g group] [-m mode] [-o owner]
               [-M log] [-D dest] [-h hash] [-T tags]
               [-B suffix] [-l linkflags] [-N dbdir]
               file1 file2
       install [-bCcpSsUv] [-f flags] [-g group] [-m mode] [-o owner]
               [-M log] [-D dest] [-h hash] [-T tags]
               [-B suffix] [-l linkflags] [-N dbdir]
               file1 ... fileN directory
       install -dU [-vU] [-g group] [-m mode] [-N dbdir] [-o owner]
               [-M log] [-D dest] [-h hash] [-T tags]
               directory ...
*** Error code 64

Stop.
make[5]: stopped making "installconfig" in /usr/src/bin/sh
*** Error code 1

[end of log excerpt]


This is my "build machine," which (as shown above) just runs GENERIC;
I don't even have a custom kernel config to sully the pristine
sources. :-}

freebeast(15.0-P)[9] git status -vv
On branch main
Your branch is up to date with 'origin/main'.

nothing to commit, working tree clean
freebeast(15.0-P)[10]

(I tried "etcupdate extract -B" on another machine that I keep
updated at the same cadence, and it had a similar whine -- which
is how I noticed this one.)

Help?

Peace,
david
-- 
David H. Wolfskill                              david@catwhisker.org
Of course firing the statistician will force the statistics to conform!

See https://www.catwhisker.org/~david/publickey.gpg for my public key.