Hi. Did you flash ROM with SPFT? If not please follow this SPFT updating instruction http://community.umidigi.com/thread-11-1-1.html
And here all available ROMs http://community.umidigi.com/forum-132-1.html
Also please contact seller for warranty. Maybe they give you some satisfying warranty option.
Otherwise if nothing help you need dissemble phone and check screen connection.
If still not working correctly please order new screen https://m.aliexpress.com/search.htm?keywords=umi+london+screen#/
Please choose option starting from around €26 as this units including screen, digitizer and glass as one unit and this option is easy to fix.
Probably there is hardware issue.
I don't see other explanation.
Is this only happening on "painting " app?
Is your screen responding touches on centre of screen on setting, games, camera when you touch centre of screen for focus, etc?
Hi
In 99.9% I am sure that in umi super is OGS glass/screen used but what is wondering me that this company which you provided link is selling only glass/touch/digitiser separately which is impossible as this is One Glass Solution unit including GLASS , SCREEN , DIGITISER .
I think that this is some fake .
Did you contact your seller ?
Does this fault happened after update ?