The upgrade to Android 10 did not go as planned for some Mi 9T and Redmi K20 handsets, with multiple people reporting high battery drain affecting their devices. While there was a workaround, Xiaomi pulled the build to address other bugs too. Now, the company has restarted the rollout of Android 10 builds of MIUI 11, although you may not notice the difference.
https://www.notebookcheck.net/Xiaomi-extends-Android-10-release-for-the-Mi-9T-and-Redmi-K20-after-pulling-initial-build.453631.0.html