Open Music Lab's Sinulator Question

[Gingoism]

I was curious to test the OML Sinulator for myself so i breadboarded the circuit with a minor change, the matched transistors which are pmp 4201/5201 were replaced with bcm847/857ds. It works mostly fine except there is an issue with the the "3rd" fold as you can see highlighted in the pics and vid below. The circuit works as expected in ltspice however and quick comparison of the voltages present at the base of the npn transistors in simulation and breadboard correspond with one another .So i am curious to why is there an anomaly?

I also noticed if Q13B collector is disconnected, i manage to get 5 seamless folds but of course i end up missing the 6 folds as mentioned in the wiki site

http://wiki.openmusiclabs.com/wiki/Sinulator

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InkedIMG_20210815_203159_LI.jpg
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Missing fold.mp4
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sinulator4_sch.pdf
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[Gingoism]

longer video...

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Sinulator.mp4
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