The JSON-LD sample for https://schema.org/PropertyValue has an example of multiple exifData properties for a photo. It fails validation using the Google Structured Data Testing tool due to the lack of commas between these properties. Adding the commas allows it to validate, however the validator only extracts the first exifData property, ignoring the subsequent ones.

What is the correct syntax for providing multiple exifData or additionalProperty properties in JSON-LD? Typically this type of data would use an array, i.e. additionalProperties?