Changes like replace, addfile, etc are currently not preserved in
pending but discarded. This is especially bad when unrecording
replace patches, since they are not so easy to restore.
I wasn't able to track this one down, other than that it worked in
darcs-2.14, but no longer in darcs-2.16.
Here is a simple test:
echo bla > bla
darcs record -lam 'bla'
echo yyy | darcs amend --unrecord -a bla
darcs whatsnew > new
grep 'addfile ./bla' new