ffmpeg Segment node "Unhandled promise rejection"

[DamonGitHub]

With reference to the video-captioning starter kit.

I deployed the starter kit in the IBM cloud. Running the placeholder demo Ted Talk through at /tv returns the error: "ffmpeg conversion failed" in node-red and "Invalid data found when processing input" in the CLI. Changing to another video resolves the issue (although many other videos fail). Firstly, ffmpeg is normally not fussy about video input, especially h.264 mp4s, which suggests a potential issue there.

Secondly, with a different video that gets past this stage, I get the following error at the 'ffmpeg segment' node:

(node:90540) 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: 49)
(node:90540) UnhandledPromiseRejectionWarning: TypeError [ERR_INVALID_CALLBACK]: Callback must be a function. Received undefined
    at makeCallback (fs.js:154:11)
    at Object.unlink (fs.js:1035:14)
    at /Users/<name>/.node-red/node_modules/node-red-contrib-media-utils/ffmpeg-segment/ffmpeg-segment.js:112:14
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

This error repeats over and over and I have to restart node-red to resolve.

There appears to be an issue with the code that is preventing me from trialling the speech-to-text with this starter node. Can you take a look and get back to me, please?