Files I cannot delete/chown/chmod as root?

[yancm%sdf.org@localhost]

On NetBSD 9_3_Stable, amd64, long time user...

I have ended up with some files that I am unable to delete as root.
# ls -las
total 6
2 drwxrwxrwx  3 root  wheel    512 May 18 09:39 ./
2 drwxrwxrwx  4 root  wheel    512 May 18 09:50 ../
2 drwxr-xr-x  2 root  privoxy  512 May 18 09:39 @test_26381_tmp_SRC/
# ls -las  @test_26381_tmp_SRC
total 4
2 drwxr-xr-x  2 root  privoxy  512 May 18 09:39 ./
2 drwxrwxrwx  3 root  wheel    512 May 18 09:39 ../

but:
# rm -rf  @test_26381_tmp_SRC
rm: @test_26381_tmp_SRC: Operation not permitted
# rm -d  @test_26381_tmp_SRC
override rwxr-xr-x  root:privoxy for '@test_26381_tmp_SRC'? y
rm: @test_26381_tmp_SRC: Operation not permitted
263 # chmod a+rwx @test_26381_tmp_SRC/
chmod: @test_26381_tmp_SRC/: Operation not permitted
264 # chmod a+rwx @test_26381_tmp_SRC
chmod: @test_26381_tmp_SRC: Operation not permitted
# chgrp wheel @test_26381_tmp_SRC
chgrp: @test_26381_tmp_SRC: Operation not permitted

I ran chkdsk on this partition and it did not find errors...

What am I missing?
--gene