The Acer flagship monitor, Predator X35 has been available for a while now and some users have seen issues with display flickering or showing vertical stripes in games.  

Acers's 2000 USD/EUR monitor offers an ultra-wide G-Sync screen with HDR1000 certification and full-array local dimming with 512 zones. the Predator X35 packs a 35-inch 3440 x 1440 VA panel with up to a 200 Hz refresh rate, 1800R curvature and G-Sync Ultimate support.

The firmware update would solve the problem and is due to "sensitivity to certain color patterns" that the LCD panel is struggling with. As far as I could see, the update is not yet available but will be in the next week or so. 

Acer Predator X35 Optional Firmware Update
Why does my Predator X35 monitor flicker or show vertical lines when gaming?

The Acer Predator X35 may occasionally flicker or show vertical lines while displaying graphics from certain games. The issue is caused by LCD panel sensitivity to certain color patterns. Acer has resolved this issue in a firmware update that will be available for download before the end of December 2019. We will update this article once the new firmware is available.

Acer Predator X35 monitors with serial numbers where the 11th-13th characters are <950 are eligible for this update. You can see an example of an impacted serial number below.

Example: MMTG4SG001924023F38511)

Acer Predator X35 Firmware Update Fixes Flickering Issues