Thanks for the video, it clearly shows you’re doing it wrong!
All kidding aside: you should always calibrate (if you feel you need to) by placing the projector on a level surface or in a level position (you can verify this with your phone if you have a level app). Once calibrated, the PPM will know what’s level, and the sensors will adjust the keystone to the proper angle according to the angle measured when tilted.
What you saw happening in the first part, prior to you starting the calibration at 0:06, looked quite alright already. It could be a little bit off, and that’s what calibration would’ve helped with, but only if carried out in a level state.
By calibrating it now in a tilted state, you threw off the correction even more, rendering it ineffective, even if you put it level it wouldn’t display correctly.
Solution: calibrate it again, but from a level position. Afterwards you should ideally not have to calibrate it again, it will know what level feels like.
Feel free to post a video where you fix it!