permanent vertical lines on display after battery replacement

I did the guide on replacing the battery of a pixel 3 with the ifixit kit.

Everything was fine after taking off the backplate, then i swapped the batterys and used 99% isopropyl alcohol to get the old battery out. After installing the new battery, the screnn showed vertical green lines.

I found multiple Questions here that found, the problem to be with the alcohol and that it would evaporate itself if you wait a while. I did so by letting it stay open during the night. The next morning, just as expected the screen was completly fine again, no lines or any other damage whatsoever.

After using the phone for half a day, the lines came back, stronger, brighter, more and diffrent colors.

I think the screen is propably broken, but I would really like to know why. What was the cause ?

Was it the force or heat of taking off the backplate? But why did it work for two day, no problem.

Was it the isopropyl alocohol ? But why did it work for half a day after having time to evaporate and why would the alcohol permanently damage the screen ?

I really hope someone can give me a bit of insight, also ideas on how to continue would be apprechiated.