Issues with 7" IPS-Display

Hi Everyone!

I've a LP Z8300 4/64 since one of the first delivery batches for the Kickstarter backers. Everything seems fine with the board it self. Just the little red power-LED did never work. But this never bothered me. After this long time and a lot of testing, I got an idea for a project as a car-PC. So I've resently ordered the 7" ISP-Display because it fits absolutely perfect.

When I connect the display while the board is not powered, I'll get those white stripes which will get more or less when something moves around on the screen - I use a HDMI monitor as a mirror screen. I have no problem with powering. Even under heavy load everything else seems fine.

As soon as I loosen the IPS-connector just enough that the display is not longer powered and fasten it again (no adjustment to the cable is done), the display works fine as long as I don't shut down or restart the board.

If I shut down/reboot the board, I'll get some ghosting effects of the last screen shown, right before the shutdown/reboot.

If I shortly disconnect the power supply before the next start up, I'll get the white stripes again.

Might this be a problem with my LP? If so, is there a possibility for a RMA after this long time?
If theres no RMA, is there something I need do to get this working?
And if theres not really something I can do, does someone know a workaround with a connection reset via soft- or hardware?

If you need more informations, just ask.
I'll try to provide some pictures as soon as possible.

Thank you and greetings,
Dog.