With:
$ rm -rf ~/.cache/guile/ccache/2.2-LE-8-3.A/home/local/
$ lepton-sch2pcb a.sch > log 2>&1

 I get the error messages
find_element can't open dir "...": No such file or directory
 as you can see in the tile log. The content of the dots ("...")
 changes between test runs.

 I doesn't matter if I move avay ~/.pcb ~/.gEDA ~/.config/lepton-eda or not,
 nor does it matter if a.pcb is present or not.

 A second run of lepton-sch2pcb (i.e. without the rm -rf ~/.cache/...),
 it behaves normally.

 lepton-eda, git checkouts
f2650636dd6bf0918e9d5d24c1b48246afc1e336 is good
045a0e2a6742ea159243fee6535443b96391797f is bad