Strange purple lines with the official Pi screen

[Cacodemon]

Tried to google this few months back, but didn't find much on the subject. I'm currently running Raspbian Stretch on Pi 3+ and the official screen. I'm getting these odd lines on my screen, usually from startup/splash or after running anything on the Pi: I'll let the attachment speak for my case. Checked the connections and didn't attach anything else to my Pi yet. Originally I had a basic Linux set up on my Pi, and the lines were there with it too... they probably were from the first day I used the screen if I recall right.

Capture.JPG (187.63 KiB) Viewed 326 times

Have I missed something or is my screen just flawed? What could be causing those annoying lines? And most importantly, how can I get rid of those lines for good? :p

[andrum99]

Try removing and re-seating the display ribbon cable at the Pi end, making sure it is inserted fully in the socket and there are no greasy fingerprints on the contacts. If that fails, try the same with the display end of the cable. Failing that, disconnect everything else from the Pi and use an official power supply to rule out power problems.

[Cacodemon]

Did so. The purple lines persist.