Why does Bing Image Search API occasionally return JSON payloads with starting letters of fields changed from "i" to "ı"?

We notice that Bing Image Search API very occasionally comes back with a response with the peculiar property that every initial i in a field name throughout the whole JSON payload is replaced by ı - U+0131 (LATIN SMALL LETTER DOTLESS I). Other occurrences of "i" are unaffected, whether in field names or other parts of the document. Why is this the case?

One theory we have internally, but of course cannot confirm, is that perhaps as part of JSON serialisation, the first letter of field names are being converted to lower case, and that in a Turkish locale, this would lead to an uppercase I being transformed to a lowercase ı. If some fraction of requests end up served from a server in that locale, this might explain the responses we sometimes see.