REPRODUCIBILITY (% or how often): 50%
BUILD ID = OS VERSION (Settings > About product): 4.0.1.48
HARDWARE (XA2, Xperia 10…): XA2 Plus
UI LANGUAGE: Russian
REGRESSION: (compared to previous public release: Yes, No, ?): 3.4.0
Had similar problems on Xperia 10 right now. Solution was to scrub the screen powerful with a linen. So I’m shure often it’s only invisible dust and dirt that irritates the touchscreen.
I experience the same bug (but with an X 5 IV) and a rather clean screen.
Never had it with my previous X 10 III with a rather dirty screen.
My bet is that scrubbing or not, the retry get you cleared (or not).
Its sad because the phone is unreliable that way, when you urgently need it, it may stay unresponsive for just too long for what you need.
I’m wondering if it’s an hardware problem or not…
( ping @rinigus )
Another thing aside from dirt and dust on the screen is the ground connection of the metal backplane of the touchscreen. This sometimes may suffer from tottering contacts. I had this problem a few times in the last 6 yrs + 4 devices.
On 2 devices, it was necessary to open the device and to electrically connect the metal backplane with chassis of the phone using a thin wire (singe wire from a power cable).
After doing so, the stucking screen problem disappeared permanently until today.
It seems that Sony phones are not always the best manufacturing quality.
The screen of the X5IV I bought second hand have been replaced before I bought it (by a Sony validated repair shop).
Things may have go a little wrong during the operation.
Did you experience any touchscreen loss during use ?
My problem is always when waking up the phone from standby. Never during use…
Yes I did. For me it looks like some processes start delayed or fail to start when waking up the device from standby, especially after looong standby time.
Short pressing Power button twice to standby and re-wake up always helps. My device then always went back to normal function.
I had this issue with my Sony XZ2 Compact when replacing the screen. The Solution for me was to reflash Android again and then reflash SailfishOS.
I’m a bit puzzled : if it’s an hardware problem it should not be the delayed unlock thing (that I have). It should appear even in the middle of a normal use…
Re-flashing things should not have effects (but OK, worth trying 
)
Based on @Seven.of.nine precious feedback and looking for a hardware problem with sporadic manifestation, I pressed firmly by fingers all around the perimeter of the screen.
[edit] it’s not magic…