The record
On October 10, 2018, a user says dictation search on their Apple TV 4K had stopped working in several apps, including Netflix, YouTube, and Plex, though only on some screens, after working the day before. They note that the remote's microphone was clearly fine because Siri still responded on the home screen and on some app home screens, and that nothing had changed on the device. The post does not mention troubleshooting steps or an OS version, and the original poster did not report a fix before the thread closed. This is one user's report.
Read the original source at Apple Support Community (opens in a new tab) ↗
A documented user report, not an independently reproduced test or an estimate of how often the problem occurs.