The device in question is an ASUS ZenFone 5Z 4GB/64GB, unrooted, updated to 100.10.107.87.
In the latest firmware update, which I'm running now, an improvement was brought to the touch panel response. Very welcome indeed.
But this improvement was not a definitive fix. In fact, it's not like before, but the problem still exists. You can still feel the lack of fluidity in the response from sliding your fingers on the screen.
For better reproduction, do the following multi-touch test on the tool accessed through the calculator:
Put three fingers together, very close together. (Also works with two, four, etc.)
Place them on top of the screen.
Slide them slowly to the bottom.
This problem does not affect the sliding of the fingers while they are separated (or the effect is less noticeable).
Another problem still present is the delay, which can be reproduced in the same tool, as follows:
Start by sliding a finger across the screen.
As you slide it, add a touch.
You will see that the response to the sliding finger will stutter before it returns to accompany the finger.
@Anders_ASUS@CH_ASUS