In attempting to test my trytond service wit hthhis line

make check-system TESTS="trytond"

I get this errror

[...]
adding user 'guixbuilder08'...
adding user 'guixbuilder09'...
adding user 'guixbuilder10'...
adding user 'trytond'...
adding user 'postgres'...
registering public key '/gnu/store/94y24as2zk3n3n39602vlanqb1g5j0c0-guix-0.13.0-12.0a154c1/share/guix/hydra.gnu.org.pub'...
ERROR: In procedure append:
ERROR: In procedure append: Wrong type argument in position 1 (expecting empty list): "-c en_US.utf8"

Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue.
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scheme@(guile-user)>

Where does this -c en_US.utf8 string come from ?

Where is append being called ?

Could I have a slighhtly more verbose error message ?

Thanks