I believe this is the bug that was fixed in 3.3.1.3.
FYI, there's no such tag pushed into the official repo.
https://gitlab.common-lisp.net/asdf/asdf/tags
using HEAD, the test case i sent doesn't fail anymore, but our own issue still prevails. it's a large environment with many systems, but the symptom looks the same, although for us due to cxml.
i couldn't easily test with an older version of ASDF because my SBCL already ships with 3.3.0.1 (preventing an easy downgrade), but it used to work until recently.
after i edit cxml.asd to follow the foo/bar convention, i see a few of these, that may or may not be the cause of the spurious reload that i still see:
WARNING: Computing just-done stamp in plan NIL for action (ASDF/LISP-ACTION:COMPILE-OP "iolib/syscalls" "ffi-types"), but dependency (ASDF/LISP-ACTION:PREPARE-OP "iolib/syscalls" "ffi-types") wasn't done yet!
WARNING: Computing just-done stamp in plan NIL for action (ASDF/LISP-ACTION:COMPILE-OP "iolib/os" "ffi-types"), but dependency (ASDF/LISP-ACTION:PREPARE-OP "iolib/os" "ffi-types") wasn't done yet!
WARNING: Computing just-done stamp in plan NIL for action (ASDF/LISP-ACTION:COMPILE-OP "iolib/sockets" "grovel"), but dependency (ASDF/LISP-ACTION:PREPARE-OP "iolib/sockets" "grovel") wasn't done yet!
please note that this is not a burning issue for us, it's just a friendly heads up with the hopes that it's useful.