I have unlocked the challenge trophy two days ago using this exploit/bug.
So i can confirm it's still effective on 2019 August the 11st on EURO version.
Thank you for the tip !
I needed some attempt to get the good timing.
What i did :
- on my left, a smartphone with stopwatch app ready
- in front of me, a computer with web browser opened on the following url : http://witness.webcrow.jp
- on my right, another smartphone ready to take picture of the maze
1/ start the challange and the stopwatch at the same time
2/ solve the few first puzzle
3/ take a picture of the maze for both triangle puzzle location
4/ solve all the puzzle until you arrive in the maze
5/ use the picture and the website to go throught the maze and solve both triangle puzzle but don't valid the 2nd one yet.
6/ when you see 6(min)38(sec)30 on the watch, press cross button to validate the 2nd triangle puzzle
7/ go check the final room, the last 2 puzzle should be waiting for you now
if not, try again but don't worry your close
good luck !