Here is a list of the times weiss uses the exploit of the model multiple times to scout out CI [(As noted by the black shadows) (https://www.youtube.com/watch?v=xlnbrewaZqw)]
0:11 (The first time) 0:29 (Used to avoid 682 and then cross the bridge where you cannot see his shadow)
1:10 (He can be seen crossing the bridge back to the elevator) (Proof that this shadow is him, when his model glitches out (https://gyazo.com/0437994681fbe85f182da27d54e54cb6)
1:30 (For the final time & when I realize)
Edit
Rewatched my full end and seen this moments before I had trimmed the start of the past video (https://www.youtube.com/watch?v=Eg-e2oWJMgI)
at 0:07 you can see him abusing his model to peak around the corner and observe the locations of the CI members before going behind cover to switch to a gun and shot at me.
^ And for this reply ^
Watching the two videos together Part 1 and Part 2 (Same engagement, just split-up) you can see Weise clearly knows we are there by shooting at me first thing (https://www.youtube.com/watch?v=Eg-e2oWJMgI 0:21)