This happened to me earlier while I was streaming, and I have a few ideas as to what it is. I know this game isn't fully optimized in the sense that you can't bug / glitch through walls, and I see this happen a lot actually. This occurs especially in the warmup session of Battle Royale games, the riot shields can be shot through if you kinda crouch and put your face forward, as your head extends outside of the shield and you are a free headshot, if this happens with the shields I imagine it could probably occur with walls, doors..etc
My next idea is lag. When you have a high ping, you can rubberband on the other players screen some, and so what appears to be (on your screen) you being inside of a building, you actually are just walking into the door. So it may seem as if you are getting "shot through walls" but actually your connection to the server is just delayed. Either of these options seems to make sense in your scenario, I wouldn't call hacks though.
This game has minor fixes like extending through walls that need to be fixed, not too big of an ordeal though.