Looks like a hardware issue with the screen ?
It's a hardware issue but probably not with the display screen itself.
The HD44780 (or equivalent) LCD controller contains all of the memory and does all of the processing required by your entire display but it only handles the display of 16 characters, those on the left half of your display. The display of the other 16 characters is handled by an HD44100 (or equivalent) auxiliary controller.
Since you are able to display characters on the left half of the screen but not on the right this indicates a problem with the auxiliary controller and/or the connections between that device and the screen.
Don