I am glad to announce that I could solve all my problems with my Lumia 1520. It has been now two weeks without any of the following:
. Bing Search popping up
. Screen freezing
. Soft buttons not working
. Soft buttons activating randomly
. Screen shaking up and down
. Screen resizing like zooming in when going to type password on lock screen
. VGA color on lock screen
. Password undesired multiple taps on lock screen
. Phantom taps
. High Battery consumption
. SD card reading issue after a soft boot
. Reboot when shutting down
. Screen stuttering
There was not a single hour before that I did not had one or more of the above annoying problems.
I am using Win 8.1, Glance, Double Tap to Wake, Cortana pinned to home screen and all the goodies.
I will report back by the weekend, but so far I am so happy that I had discovered the root cause. If the fix that I have described in my previous post really worked, I will write and share a detailed tutorial to help those that, like me, are not covered by a warranty on their phones.