Hi Nick,
It seems all languages still have "System Dashboard" in English, although there is one instance translated on the Transifex Back End project (details below).
I've checked a few languages and they are all behaving in the same manner. Note on screenshot 2 there is one localised instance of System Dashboard on the left side bar, so the string in Transifex might be that one instead. Searches in Front End came up empty.

Please see screenshots of EN, BR and FR attached.

Key
admin.menu.globalsettings.default.dashboard
Resource
jira_cloud_i18n.properties
String Hash
ad955f8de34767315b2bdc8bf4542640

Thanks
Luisa