The month name “Zĩ-likr kiuugu” is ambiguous between September and October in MediaWiki’s current Mossi (mos) translations, and the month name “Moranang” is ambiguous between March and April in the current Tswana (tn) translations:

$ git grep -e 'Zĩ-likr kiuugu' -e Moranang
languages/i18n/mos.json:	"october": "Zĩ-likr kiuugu",
languages/i18n/mos.json:	"october-gen": "Zĩ-likr kiuugu",
languages/i18n/mos.json:	"sep": "Zĩ-likr kiuugu",
languages/i18n/mos.json:	"oct": "Zĩ-likr kiuugu",
languages/i18n/nso.json:	"april": "Moranang",
languages/i18n/nso.json:	"april-gen": "Moranang",
languages/i18n/nso.json:	"apr": "Moranang",
languages/i18n/tn.json:	"april": "Moranang",
languages/i18n/tn.json:	"april-gen": "Moranang",
languages/i18n/tn.json:	"mar": "Moranang",

One consequence of this is that dates may be confused in Wikidata: with a Mossi user interface, a date that was originally entered as 2023-10-01 may be displayed as “1 Zĩ-likr kiuugu 2023”; when edited again, this same string may now be parsed as 2023-09-01. (Because only sep but not september is affected, that date is then displayed at “1 Bõn-biuungo kiuugu 2023”, but users may not notice the difference before saving their edit.) I made this edit by only adding and then removing again a space at the end of the text input.

Out of the editors of MediaWiki:sep/mos, MediaWiki:oct/mos, MediaWiki:mar/tn and MediaWiki:april/tn on TranslateWiki.net, I can only see a Phabricator account for @RebelAgent; I’ll contact the others on their talk pages.