Bing Custom Search - how are result MetaTags formatted?

Question

Given the following meta tag in a web page

<meta name="search.date" content="22/05/2018 00:00:00">

Using Bing Custom Search API to get this result, in Page.searchTags, it appears as

"searchTags": [{
  "name": "search.date", 
  "content": ""22\/05\/2018 00:00:00"; 22; 05; 2018; 00; 00; 00"
}]

Can anybody make sense of the funny format and repeated data? There's no mention of it in the docs.