I have made a circuit update for 7.99 at More simulation examples for KiCad/Eeschema/ngspice - #4 by holger.
This is an oscillator circuit with all its quirks, especially the start-up of the oscillator depends on tiny details of the simulation setup. I have added a start-up pulse to allow early starting of the oscillation. And due to its using CMOS it is inevitable to not set ngbehavior to ps.