3 Softclipping section breaks the simulation

[rossbalch]

Not quite sure how to document this, but if I ever add more than 2 soft clipping sections to a schematic, the simulation exhibits very strange behaviour with too much clean signal and sup-optimal harmonic characteristics that aren't present with two or fewer softclipping circuits.

This one exhibits strange behaviour

This circuit appears to simulate as expected.

I can supply schematic files if requested.