Off by one routing error when using AUX send matrix

The matrix works correctly when no plugin is in the AUX send's destination bus or the plugin is deactivated. I noticed it with CALF sidechain compressor, LSP sidechain compressor stereo and LSP mixer. In the example session I use LSP mixer. A stereo track is AUX sent to channel 3+4 of the 4ch bus. - Switch the LSP mixer plugin off and everything is ok. - Switch the LSP mixer plugin on, open its GUI and you see that inputs 2+3 get the signal instead of 3+4. [matrix.qtz.zip](https://github.com/user-attachments/files/21553515/matrix.qtz.zip)