As a workaround when this bug happens, deleting the (remote) files mentioned in the log as "Ignored" seems to work:
File duplicity-full-signatures.20181020T154202Z.sigtar.gpg is not part of a known set; creating new set
Ignoring file (rejected by backup set) 'duplicity-full-signatures.20181020T154202Z.sigtar.gpg'
File duplicity-full-signatures.20190119T143326Z.sigtar.gpg is not part of a known set; creating new set
Ignoring file (rejected by backup set) 'duplicity-full-signatures.20190119T143326Z.sigtar.gpg'
File duplicity-full-signatures.20190119T143326Z.sigtar.gpg.1 is not part of a known set; creating new set
Ignoring file (rejected by backup set) 'duplicity-full-signatures.20190119T143326Z.sigtar.gpg.1'
File duplicity-full-signatures.20190119T143326Z.sigtar.gpg.2 is not part of a known set; creating new set
Ignoring file (rejected by backup set) 'duplicity-full-signatures.20190119T143326Z.sigtar.gpg.2'
As a workaround when this bug happens, deleting the (remote) files mentioned in the log as "Ignored" seems to work:
File duplicity- full-signatures .20181020T15420 2Z.sigtar. gpg is not part of a known set; creating new set full-signatures .20181020T15420 2Z.sigtar. gpg' full-signatures .20190119T14332 6Z.sigtar. gpg is not part of a known set; creating new set full-signatures .20190119T14332 6Z.sigtar. gpg' full-signatures .20190119T14332 6Z.sigtar. gpg.1 is not part of a known set; creating new set full-signatures .20190119T14332 6Z.sigtar. gpg.1' full-signatures .20190119T14332 6Z.sigtar. gpg.2 is not part of a known set; creating new set full-signatures .20190119T14332 6Z.sigtar. gpg.2'
Ignoring file (rejected by backup set) 'duplicity-
File duplicity-
Ignoring file (rejected by backup set) 'duplicity-
File duplicity-
Ignoring file (rejected by backup set) 'duplicity-
File duplicity-
Ignoring file (rejected by backup set) 'duplicity-