Touchscreen problem?

Question

Android

Good afternoon!
Please suggest what could be the reason.
There is a Leagoo Alfa 5 phone Kernel
version: LEAGOO Alfa 5_OS1.1_Lite
Communication module firmware: LEAGOO Alfa 5_OS1.1_Lite Build
number: LEAGOO Alfa 5_OS1.1_Lite_20160623
The problem is that the touch screen started to be pretty stupid ... or is it a system glitch ...?
see the picture from paint'a from the phone.

spoiler

the meaning is that when drawing straight lines, it draws a V shaped line.