The i18n entries for MediaWiki:Grouppage-functioneer and MediaWiki:Grouppage-functionmaintainer currently point to the main namespace. They need to point to the project namespace.

I.e. Currently incorrect:

• https://github.com/wikimedia/mediawiki-extensions-WikiLambda/blob/master/i18n/en.json#L15-L18

Should be:

• "grouppage-functioneer": "{{ns:project}}:Functioneers"
• "grouppage-functionmaintainer": "{{ns:project}}:Maintainers"

Temporary fix:
I've temporarily fixed with local overrides, which should be deleted once this is fixed and merged. (at MediaWiki:Grouppage-functioneer and MediaWiki:Grouppage-functionmaintainer)