Perfectly developed games don't exist and there are always a few little bugs lying around. This is even more the case with games like Valorant that run on regular cycles of updates and balancing. Players have discovered a new bug that allows wallhacking a door on Ascent.
The bug would have appeared after the last patch. It allows you to see through the sliding door of A, when you look through the switch that activates it. If you can't see perfectly, as shown in the video, you can distinguish the shapes of the enemies. You can clearly see in which direction they are going and which agents they are.
It's a glitch that gives very valuable information, especially since it allows you to see without being seen because there is only one switch. Riot Games has dedicated a team to solve the issue and the bug should be fixed soon.