This is a follow up to P2071 in a sense as this aims to solve the issue occuring (or solve) on other lists under a similar circumstance.
After looking at encoding of private lists, the following need to be fixed:
mediawiki-sv
ruwikiconference-l
wikics-l
wikiis-l
Some are closed but that shouldn't affect the status of closing this as it is a fatal bug in mailman.