I would feel uneasy as well if it just fixed itself.
I havent experienced any artifacting like that. Looks like some pretty good damage to the speaker grill. The hinges on this laptop are VERY sturdy and robust. There's no give whatsoever so if something was placed under the screen and it was closed, I wouldnt be surprised if it pushed enough in to cause something to pinch and damage. The ribbon for the display could run in that area under the bezel. Hard to say without tearing down the display.
Im also not even sure Asus would cover this repair under the ADP:
https://www.asus.com/us/support/article/693/"ASUS ADP does NOT apply to the following: scratches and dents"
(ROG has simply become too expensive compared to the competition with same specs... 😞 )
MSI GE75 Raider 10SGS - i7 10750H - RTX 2080 Super - 32GB Ram - 1TB WD NVMe - 2TB 960 EVO - 300Hz 17inch Display
RETIRED: ALIENWARE R17 R5 - i7 8750H - GTX 1070 @ 1.9Ghz - 16GB DDR4 - NVMe 970 EVO 1TB - SSD 960 EVO 1TB
SOLD: ASUS G703VI-XH74K, RETIRED: ASUS G752VY-DH72, RETIRED: ASUS G750JH DB71 , RETIRED:ASUS G74Sx DH72