Custom nested ordering no longer working.

[slegay]

The document schema has a 'content' property, which is an array of objects, each having a 'term' and 'locale' properties.
We want to order those in the studio by the first content objects' term property. This used to work fine by declaring this ordering:

    orderings: [
      {
        title: 'English Term',
        name: 'termEnAsc',
        by: [
          {field: 'content[0].term', direction: 'asc'}
        ]
      },
    ],

However this no longer works, we get the following error in Studio:

Error: The current ordering config targeted the nonexistent field "content[0]" on schema type "glossaryTerm". It should be one of slug, content, childTermsRefs, synonyms, relatedTerms

We tried the preview selector syntax content.0.term, but that won't work either. Error: unexpected token "0.", expected expression

It seems impossible to select a property of a nested object within an array for ordering. But that used to work just fine. I would expect the sort order field selector to work the same way as the preview title selector, content.0.term, which works fine.