Following request #14155 those errors can be seen when running the Jest test suites:

(node:107400) UnhandledPromiseRejectionWarning: [object Object]
(node:107400) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:107400) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:107400) UnhandledPromiseRejectionWarning: [object Object]
(node:107400) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)


This is due to a behavior change in one of the updated library but the changes should have been found by our test suites and not silently ignored.