I found a very strange issue. It is a crosstalk issue. The left channel bleeds into right, and vice versa.
Have a look at this screen recording:
![Image](https://i.imgur.com/6PYSIUK.gif)
I'm using PATCH INSERT, and sending to the first and the second channel strip the same signals. The sound is alternating between left and right channels. As you can see above, the first strip has crosstalk issue. I can hear the sound bleeding to the other side. The issue shows up only in the first strip.