Something wrong with .fasb support
A test in the ASDF test suite reveals brokenness in ECL fasb support.
cd .../asdf make t l=ecl t=test-xach-update-bug.script
==> It works!
Now try again after uncommenting this line near the top of the file:
(setf asdf::*load-system-operation* 'load-bundle-op)
==> It fails!
The problem seems to be a conflict in package handling when trying to load from both fasl and fasb, or something.