When a download in git lfs smudge is cancelled, it sometimes leave some trash in .git/lfs/objects:

$ ls -al .git/lfs/objects/ab/cd
total 43928
drwxr--r--  4 rick  staff    136 Apr 28 08:02 ./
drwxr--r--  3 rick  staff    102 Apr 28 08:02 ../
-rw-r--r--  1 rick  staff      0 Apr 28 08:02 abcd...
-rw-r--r--  1 rick  staff  13523 Apr 28 08:06 abcd...-temp

On a second git checkout, the 0-length file gets moved over to the working directory. My hunch is that the file gets opened for file locking purposes, but never cleaned up because the command was aborted.