U2713HM, scanlines, buzzing sound

Hi,

As stated above, my U2713HM I bought recently for graphics behaves very  strange in some cases. When there are some specific images on screen monitor switches to some sort of vertical interlaces mode that alter the screen overall brightness. Every even vertical line is dominated by color magenta, and every uneven by  yellow/greenish. Its very disturbing as its alters all colors temperature. Please look attached images and display them full screen native monitor resolution 2560x1440 ( 1 pixel of image = 1 pixel of display ) :

hatch A0 - mid gray color, its okay

hatch A1 - mid gray color with pattern, which trigger monitor to  interlaced mode : from plain gray. now it switches to colored lines if you look closely. it is just wrong if monitor switches display modes "unasked" during work. also the image looks ugly in that "mode", whatever it is. interlacing is clearly visible if you look closely, and doing graphics you usually do so. from distance  of lets say 50 ck from monitor, if this triggers, it looks like screen alter its brightness.

hatch A2 - like above, only zoomed version of A1 - no interlacing, but buzzing sound appears. if you zoom further, buzz will lower its frequency further with every step you enlarge it.

I work a lot doing graphics and this unwanted, unnecessary and erroneous interlacing messes things up, there should be stable color representation, regardless if there are dots or checkers on the screen, so this is unacceptable and not mentioned in monitor specification. my question is : how to get rid of this annoying and unacceptable interlacing effect that is not mentioned within monitors specifications nor in monitor menu? ( hatch_A1.png )  do all 2713HM's do that?

interlace is visible on all monitor modes and on different computers, and its triggered by the display itself, so it must be a monitor's fault. cables are fastened properly. image sharpening mode is at 50 and it is fine because its totally useless because destroys the image quality on value anything other than 50 so probably off, no smoothing, no sharpening. also checked that it has nothing to do with dell display manager because tried uninstalling it and restarting system without it. vertical lines still appeared in certain conditions.