Question Vertical monitor display issue

[unitesu1]

Hi there - I have a Asus Proart display I was using as my primary display until I got a Dell to replace. Then I turned the Asus vertically to use as a second monitor. Now I'm getting the weird issue creeping from the left side as shown in the image. Any ideas on what is happening and how to fix?

 

[Ralston18]

Which ProArt display model?

How is the display mounted?

My thought being that the vertical orientation may be stressing the frame and thus the actual display?

 

[unitesu1]

Thanks for the response!

Asus ProArt PA278QV, a 27" monitor. It's rotated to 90 degrees and not mounted on anything except its own support (which according to the manual I read should be ok). It's 3 and a half years old.

It's an interesting thought, but the monitor was specifically designed to be vertically oriented - does that mean maybe I just got a lemon and didn't know it because I had it horizontal this whole time? Would doing a VESA mount perhaps fix?