Pirkle's WDFTunableButterLPF3 instantiation, no sound out from processAudioBlock()?

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Okay, I figured it out, and thought I’d leave the solution here in case anybody else ever gets stuck trying to use this.

In fxobjects.h from Pirkle’s site, this is the code for the function WDFTunableButterLPF3::setFilterFc():

/** parameter setter for fc */
void setFilterFc(double fc_Hz)
{
	if (useFrequencyWarping)
	{
		double arg = (kPi*fc_Hz) / sampleRate;
		fc_Hz = fc_Hz*(tan(arg) / arg);
	}

	seriesAdaptor_L1.setComponentValue(L1_norm / fc_Hz);
	parallelAdaptor_C1.setComponentValue(C1_norm / fc_Hz);
	seriesTerminatedAdaptor_L2.setComponentValue(L2_norm / fc_Hz);
}

The problem is that setComponentValue() does not update the A and B coefficients of the parallel and series adaptors, respectively. And those coefficients are what control the reflected summations and consequently the filter cutoff.
There are probably better ways to fix this, but since the coefficients get called in the WdfAdaptorBase::initialize() functions, I just re-initialized the chain at the end of the cutoff-setting function:

/** parameter setter for fc */
void setFilterFc(double fc_Hz)
{
    if (useFrequencyWarping)
    {
	    double arg = (kPi*fc_Hz) / sampleRate;
	    fc_Hz = fc_Hz*(tan(arg) / arg);
    }

    seriesAdaptor_L1.setComponentValue(L1_norm / fc_Hz);
    parallelAdaptor_C1.setComponentValue(C1_norm / fc_Hz);
    seriesTerminatedAdaptor_L2.setComponentValue(L2_norm / fc_Hz);

    /* re-initialize */
    seriesAdaptor_L1.initializeAdaptorChain(); // changed impedances impact A and B coefficients of adaptors
}