Hi!
I, as many others, have ghosting image problems. If you have a lgd screen, you might have it too.
I don't think I had this problem before burning custom roms...
My first rom was LOS 14.1, and it asked you to update firmware before burning LOS.
So here's my theory.
As it asked to get them...
Finally, I had to type nothing, I noticed a line when updating "successfully decrypted with default password" (whatever it was, I didn't encrypt my phone)
When I downloaded the image through the updater, a message reminds me to enter my password as internal data partition is encrypted... But it wasn't, and I just don't know any password for it