I have ubuntu 18.04 with ru locale and same issue
How I fixed it:
install snap versions
snap install duplicity --classic
snap install deja-dup --classic
remove apt version of deja-dup
sudo apt purge deja-dup
backup (option)
sudo mv duplicity duplicity_apt
link duplicity bin from snap pkg
sudo ln /snap/bin/duplicity /usr/bin/duplicity
I have ubuntu 18.04 with ru locale and same issue
How I fixed it:
install snap versions
snap install duplicity --classic
snap install deja-dup --classic
remove apt version of deja-dup
sudo apt purge deja-dup
backup (option)
sudo mv duplicity duplicity_apt
link duplicity bin from snap pkg
sudo ln /snap/bin/duplicity /usr/bin/duplicity