Json-LD structured data shown as wrong by google testing tool - schema.org

Question

With the following JSON-LD structured data, an error is thrown by the google testing tool :
{
"#context": "http://schema.org",
"#type": "Person",
"name" : "Brent",
"makesOffer" : {
"#type" :"Offer",
"priceSpecification" : {
"#type" : "UnitPriceSpecification",
"priceCurrency" : "USD",
"price" : "18000" },
"itemOffered" : {
"#type" : "Car",
"name" : "2009 Volkswagen Golf V GTI MY09 Direct-Shift Gearbox",
"description" : "2009 Volkswagen Golf V GTI MY09 Direct-Shift Gearbox in perfect mechanical condition and low kilometres. It's impressive 2.0 litre turbo engine makes every drive a fun experience. Well looked after by one owner with full service history. It drives like new and has only done 50,000kms. (...)",
"image" : "2009_Volkswagen_Golf_V_GTI_MY09.png",
"color" : "Black",
"numberOfForwardGears" : "6",
"vehicleEngine" : {
"#type": "EngineSpecification",
"name" : "4 cylinder Petrol Turbo Intercooled 2.0 L (1984 cc)"
},
"numberOfAirbags" : "6"
}
}
}
The error thrown is : You must indicate offers, review or aggregateRating.
But this data is a generic sample provided by schema.org on their car markup page.
So why does Google pop an error when using the approach recommended by schema.org ?
To clarify, the data goes as follow :
Person
-> makesOffer
--> itemOffered
---> car
And it seems Google will throw an error any time you follow that path (a person offering something)

Answer 1

The errors and warnings from Googles testing tools are often related to the structured data required to get rich snippets in Google. In this case, your markup does not fit the product requirements to get rich snippets.
https://developers.google.com/search/docs/data-types/product
As your markup does not relate to those rich snippets, you can ignore the error.