I found the same. I once computed a high-order (something like 100) low-pass Butterworth using SOS sections as a test and did not notice any instability in the

I found the same. I once computed a high-order (something like 100) low-pass Butterworth using SOS sections as a test and did not notice any instability in the filtered signal. The key was to directly derive the SOS coefficients using bilinear transformation.