Monitor Flashing on Dell Inspiron 7000 Series 7559, not showing in lcd test, not caused by movement

My computer monitor on my Dell Inspiron 7000 Series 7559 has been flickering for around a month. It is not worsened by screen movement, and does not show up in recordings or on another monitor. There are small black lines that blink on, and parts of the screen flash black. There seems to be no pattern to the flashing, but it usually happens every 5 seconds or so. While the flashing does not occur during the LCD test, it flashes in the BIOS. The intensity of the flashing changes depending on the window that is open on my computer. The desktop is by far the worst, with the screen being almost completely blacked out whenever it is visible. One page on chrome could be fine, and the next could flash like a strobe light. While I think it could be a loose cable, the changing of the intensity depending on the window is very odd, and it being unaffected by monitor movement is also confusing.