HDR content was enabled on YouTube Android app back in September, but still not many smartphones actually support it. However, even those that do support it are struggling on higher resolutions in terms of performance. Users are reporting that videos often stutter.
Because of that, Google has decided to limit the HDR support in YouTube app. The 1440p (or higher) HDR videos have been completely removed from the mobile apps and the maximum option for HDR in YouTube is now 1080p. Hopefully Google can fix the performance issue very soon.
