Mailman's import21 when importing *_these_nonmembers keeps addresses as well as regexps in the imported attribute.
import21
intends to keep only the regexps in the imported *_these_nonmembers
attribute as the addresses are added as role nonmember with appropriate moderation_action. However, the imported list ends up with the addresses as well as the regexps in *_these_nonmembers
.
This can cause problems because *_these_nonmembers
trumps the nonmember's moderation_action
rendering changes to the latter ineffective.