Hello,
I just tested this algorithm and all 4 filters are working for me. How are you routing audio to the algorithm? Note that filter #1 is for I/O 1, filter #2 is for I/O 2, etc., so if you are just routing audio to I/O 1, this may explain your issue. Also note that the “master filter parameters” will override the individual parameters, so this may be causing your issue as well. I found that if I load the algorithm and leave the master filter parameters at the default state, I was able to use a high pass filer for 1 and a low pass filter for 2. Let me know if this helps.