Samsung's software rollout speed has improved leaps and bounds from its Touchwiz days. The company was quick to launch the One UI 4 beta program for its current flagship lineup — the Galaxy S21 series — within days of the Android 12 Release Candidate going live. After a couple of months of beta testing, Samsung started rolling out the final One UI 4/Android 12 update for the Galaxy S21 series from mid-November. However, despite its best efforts, some bugs have inadvertently made their way into the final One UI build. One such bug breaks the adaptive refresh rate on the Galaxy S21 series and locks the display to 60Hz, leading to a janky scrolling experience in apps.

There have been a plethora of reports from frustrated Galaxy S21 owners about this on Reddit complaining about the poor scrolling performance and UI lag post the update. Android 12 promises smoother system performance and animations, but S21 owners were instead greeted with UI stutters. The issue only affects the Snapdragon-based Galaxy S21 variants sold in the US, with international Exynos models not exhibiting such behavior.

The bug was also present on the fourth One UI 4 beta, and while Samsung did put some fixes for it in the final public release, it doesn't seem to resolve the issue altogether. The good thing is that a Samsung US beta moderator has acknowledged the problem and confirmed the company is working on fixing it, especially since it impacts a large number of users.

Until Samsung gets around to rolling out a firmware update to fix this bug, you can manually switch your Galaxy S21's display to run at 60Hz. That should help resolve the stuttering and poor scrolling experience, for now. Alternatively, if you have not updated your device to One UI 4/Android 12 yet, you should wait until the company rolls out a new build.

Update:

UPDATE: 2021/11/24 15:40 EST BY RAJESH PANDEY

Slowly being fixed

To fix the adaptive refresh rate bug, Samsung has rolled out a new BUK9 firmware update for Galaxy S21 units on Verizon's network. This second One UI 4 and Android 12 update ensures the display stays at 120Hz while scrolling through lists, but it only seems to be working in first-party apps for now. Many users on Reddit are still reporting lag and stuttery animations while scrolling in third-party apps like Discord and Twitter. This update may be a stop-gap fix from Samsung until it can fully resolve the issue.

For now, the BUK9 firmware is only live on Verizon's network, but it should soon make its way to other US carriers and unlocked S21 units.