Flickers white line, procedes to boot to black screen. Not cracked.

Hello iFixit community! I am repairing an M1 MBP for one of my friends. I previously replaced the display and it has been working fine for a few months. However, she says it showed a white rectangle and then went black one day. I can still see something going on with the external display. Any ideas? Thank you in advance!

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crwdns2889612:0crwdne2889612:0 0


Can you post a picture or two so we can see the internals image is so we have an idea what you are seeing Adding images to an existing question