Signal inlets 2+ won't work

I'm working on an external with five signal inlets, and I can't seem to get any input from inlets 2 onward. I've included the project folder (an Xcode project) and the compiled external as an attachment, in case anybody wants to try those out. Here is my perform routine.

void rhythm_perform64(t_rhythm *x, t_object *dsp64, double **ins, long numins, double **outs, long numouts, long sampleframes, long flags, void *userparam)
{
    t_double *in3 = ins[2]; //works if I change to ins[1] or ins[0]
    t_double *outL = outs[0];
    t_double *outR = outs[1];
    int n = sampleframes;

    //fields
    int len = x->length;
    int wCount = x->writeCount;

    while (n--) {

        //write values to array
        if (wCount > len-1) {
            wCount = 0;
        }
    *outL++ = wCount;
        *outR++ = *in3++;

        //increment count and update value
        wCount++;
        x->writeCount = wCount;
    }
}

The code above will not get any output from outR. However, when I change the inlet declaration to 'ins[1]' or 'ins[0]', those inlet's input is passed to the second outlet, as expected.

Here is my new instance routine, in which the inlets are initially created:

void *rhythm_new(t_symbol *s, long argc, t_atom *argv)
{
    t_rhythm *x = (t_rhythm *)object_alloc(rhythm_class);

    x->m_outlet3 = floatout((t_rhythm *)x);

    if (x) {
        dsp_setup((t_pxobject *)x, 5);

        outlet_new(x, "signal");
        outlet_new(x, "signal");
    }

    return (x);
}

As you can see, I HAVE created 5 inlets.

I haven't found anything related to this in the documentation or the forums so far, so any help would be much appreciated.