Response field reason removed

What changed

Reads of this field return undefined, and the failure surfaces wherever that value is used rather than at the call.

Affects UserEvent reachable from 1 operation.

Who is affected

Code that reads Vercel's UserEvent objects, used by 1 Vercel operation.

Before and after

Code that breaks

// response.payload.data.reason is now undefined
const reason = response.payload.data.reason;

Based on Vercel’s published API specification. How severity is decided.