Weird LCD behavior MK3  

Weird LCD behavior MK3

So... i ahve been having some werid behavior with my LCD

1) the screen flickers when it is printing and when it is on idle.. here is a video showing this flicker: https://drive.google.com/open?id=1FCD4KI_knWb5RYr5cKG9GhpJK-c9VO19

The flickers happens every 10 seconds ( i timed it..so it seems clocked..)

the flickers was happening on 3.3.1 and it still on 3.4.0.

2) when printing using the SD card, when print finishes, i get weird symbols ( the hot end symbol disappears, i get a "° "symbol after the Print Done Message and some "##" and i need to reset the printer in order to get back the normal symbols... i did not notice this happening when printing using Octoprint... i checked the cables... i checked the connections.... didt notice anything... i mean i tried to move the cables to try and trigger it but nothing...

PS: this is my 3rd screen: the first one had dead pixels, the second one was not booting correctly. this one is perfect... just these issues.... the flicker issue was present on all 3 screens... I dont know abt the screen symbols since i was only printing using octoprint.

Thanks