Simile: moment construction falls back to js Date

I get this warning message when I look at the developer's console:
[Warning] Deprecation warning: moment construction falls back to js Date. This is discouraged and will be removed in upcoming major release. Please refer to https://github.com/moment/moment/issues/1407 for more info. (simile-public.js, line 1)

I don't know what that means and what to do about it. Does anyone know?