Error on Fresh Install: "ConcreteSocialLinksAttribute is not defined"

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Just did a clean install of c5 8.4.4 (via GUI on Windows). Tried to change admin username but can't. Possible cause: javascript error on page dashboard/users/search/view/1: "ReferenceError: ConcreteSocialLinksAttribute is not defined".

I tried with and without default content.

Gondwana