It surfaced in that HTML <meta> name attribute values are case insensitive, and it's best to use kebab-case instead of camelCase.
Guise Mummy metadata processing, e.g. and GUISE-97, now handles the conversion from HTML <meta> attribute to page metadata and back to HTML. This generated <meta> name attribute value is added at the time of generation and never parsed afterwards, but nevertheless the same principle applies.
Accordingly change the generation timestamp <meta> name from generatedAt to generated-at.