  The Sun, aside from its eleven year sunspot cycle is additionally subject to
long term variation in its activity. In this work we analyse a solar-like
convective dynamo simulation, containing approximately 60 magnetic cycles,
exhibiting equatorward propagation of the magnetic field, multiple frequencies,
and irregular variability, including a missed cycle and complex parity
transitions between dipolar and quadrupolar modes. We compute the turbulent
transport coefficients, describing the effects of the turbulent velocity field
on the mean magnetic field, using the test-field method. The test-field
analysis provides a plausible explanation of the missing cycle in terms of the
reduction of $\alpha_{\phi\phi}$ in advance of the reduced surface activity,
and enhanced downward turbulent pumping during the event to confine some of the
magnetic field at the bottom of the convection zone, where local maximum of
magnetic energy is observed during the event. At the same time, however, a
quenching of the turbulent magnetic diffusivities is observed, albeit
differently distributed in depth compared to the other transport coefficients.
Therefore, dedicated mean-field modelling is required for verification.
