Nia Kobo Nia Screen fading

Hi all,

I have tried my hand at fixing a Kobo Nia with a broken screen, Everything seems to work fine now, except some weird fading that I have never seen before.

It happens mainly in the menu's (never in the books) where the ink starts to fade after a while. Usually this happens in mere seconds as well. I added some pics to show what it looks like.

Now i'm not quite sure if the problem is with the screen or with the motherboard.

I tried searching for this problem, but I haven't seen any other forms or posts like this.

Has anyone every seen anything like this before? Does anyone know what is happening here and what could be the problem?

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