I have Acer XB323UGP since November. The first time these lines appeared in December, but I thought it was GPU (and a new one was arriving the next day anyway). And with the new GPU it never happened (until today).
Today they appeared again and it seems permanent.
Not just lines, but freezing pixels and flickering.
Checked with 2 GPUs and 2 laptops.
Three different cables both DP and HDMI.
With different modes and settings.
The main issue for me now is that I need to send it back and pack it.
And it's huge...Here's how it looks: