With REST API, there's no way to create a question with "tag" (single selection) type, and also have multiple choices. The only way to create a 'tag' question is with a single choice in the array, otherwise either a null exception or an error JSON is returned.
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Even though in API tool It is giving an error, the POST is working on multi-choice question without any issue.
So error needs to be ignored.
Zendesk Ticket Number
25561
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