I might actually believe that Microsoft is silently replacing "fixed" touch panels on those units that were sent on repair. I tried to view the sensors on my touch panel as well, no matter how I try to put a light on every angle I can't see it unlike that of msirapian.
I can still use my device but it is quite annoying to know that those issues still exist. I am just using a screen guard so I don't notice the bug that much. And I don't think replacement touch panels are available in my country.
I am from the Philippines.
I've just been to a service center in the Philippines (claimed my L1020 after repair) and I saw a lady queue up ahead of me, in her hands was a box that looked exactly like the box of my L535*. I couldn't hear her conversation with the service center representative though, but I heard the words "hindi nag-ch-charge" (not charging) and "nagloloko yung screen" (screen doesn't respond as expected).
You may contact the official Twitter handle of Lumia and inquire about their stand on the L535 screen issue, if the service center will replace the screen under warranty:
@LumiaHelp.
Or you may contact the official service center if you want before going there and check if they are aware of the screen issues of the L535.
I didn't have the screen of my L535 replaced since a recent update seemed to have improved the screen reliability - there's actually a whole
thread on that here in the forums.
And welcome to Windows Central.
*- Not sure if was an L535, though. Her hands were covering the print and she was at least 10 feet away.