Analytics/v2/details/interactions returns null for wrapUpCode

We’re pulling interaction details via the Node.js SDK (analyticsApi.getAnalyticsDetailsInteractions). The response is 200 OK, but wrapUpCode is consistently null even when agents clearly selected one. We’ve verified the groupings include wrap-up-code and the date range covers the interactions. Is this a known SDK serialization bug, or are we missing a specific query parameter to force the attribute population?