The firmware of the touch screen in Galaxy S24 Ultra mishandles some swipe gestures, either ignoring them or interpreting them as single touches.
This is supported by other posts on Samsung Community and across the Internet.
I was able to reliably reproduce the issue as follows:
In Developer options, enable "Pointer location" to visualize the touch screen input that the system receives.
To be able to quickly recognize the firmware failing to interpret a touch event, open any application with scrollable content, such as the main activity of the Settings app.
Start doing repeated swipes up and down, trying to start each next swipe as close as possible to the exact point where the previous one ended, but in the opposite direction. By the point I mean the physical point on screen, not the virtual list item.
For me, it is easy to reproduce the issue by doing around 1-2 swipes per second.
In this experiment, I noticed that:
If I manage to start the next swipe close enough to where the previous one ended, the touch screen misinterprets some swipes and treats them as single touch events (around one in 10ā30 swipes ā perhaps that's the limit of my precision).
Some swipes are ignored completely ā that's another kind of misinterpretation by the firmware. The fact that the gesture is ignored is demonstrated by the previous gesture's line still being shown by the "Pointer location" overlay.
Waiting longer than 0.5-1 second before the next swipe does not have any effect, and even after a few seconds of inactivity, if the next swipe starts close enough to where the previous one ended, it still gets misinterpreted or ignored.
Changing settings like "Touch sensitivity" or "Accidental touch protection" has no effect on this issue ā I can reproduce it with any combination of these two options.
It is worth noticing that the issue does not reproduce if, instead of doing the repeated up and down swipes with one finger and trying to match the end and start positions of the gestures, I intentionally do the swipes with two fingers (one for swipes up, the other for swipes down) and in different areas of the screen ā in that case, there is no misinterpreted or ignored gestures.
I have also tried to reproduce the issue with my previous phone, Galaxy S23 Ultra, and that device did not manifest the problem in any way.
In daily usage, I face this issue several times per hour of active usage, sometimes many times a day. The typical case is that I scroll some list or a page, and then I want to stop it from scrolling at some location, or scroll backwards because I missed the item I was looking for. So I do either a tap or an opposite swipe, which lands close to where the first swipe ended. And that gets misinterpreted. Sometimes, if the firmware mistakenly interpretes a swipe as a tap, it results in an accidental "click" on some UI element, which has several times led to a undesirable misclick for me.
Overall, it leaves very bad impression of the responsiveness and reliability of S24 Ultra, and I insist that this is a software defect in the processing of touch screen inputs.
It would characterize Samsung as responsible maintainers of their products if they fix this issue in a software update.
I reported a similar issue to Samsung Support from my S24 Plus, which I noticed immediately after receiving the One UI 6.1.1 update earlier this month. I'm exclusively (as much as possible) a glide-typist on the phone, and interrupting the touch input in that way made it very difficult to type.
I got a response the next day that developers were working on a patch, but after a week and a half I couldn't wait any longer and reset the phone to see if that might help. I'm no longer having the problem after the factory reset.
This issue happens only with the S24 Ultra. I visited a Mall with 3 different shops with S24 Ultra, and I can repeat this bug on them.
BTW, my own S24 Ultra has the same issue, and just 10 minutes ago, I did a factory reset and lost all my data without any fix. The issue is still there.
