Yes there is an initialisation issue:
gFilters.resize(NUM_CAP_CHANNELS, Biquad::Settings({.fs = context->audioSampleRate, .type = Biquad::lowpass, .cutoff = filterCutoff}));
should be
gFilters.resize(NUM_CAP_CHANNELS, Biquad::Settings({.fs = context->audioSampleRate, .type = Biquad::lowpass, .cutoff = filterCutoff, .q = 0.707, .peakGainDb = 0}));
Thanks for reporting this, we'll get it fixed upstream soon.