Minor ticks don't work with tickformat %Y and ticklabelmode period

Minor ticks don't work as expected when the following three axis properties are combined:

  xaxis: {
    tickformat: '%Y',
    ticklabelmode: 'period',
    minor: {
      ticks: 'inside'
    }
  }

The minor ticks don't show up. Changing the tickformat to anything below the year frequency (e.g. %b %Y) lets the minor ticks appear. Removing the ticklabelmode also makes the minor ticks appear.

Here is a codepen that demonstrates the issue:
https://codepen.io/Djeramon/pen/vYQzPOa
Expected behaviour: Minor ticks should appear.

It is unclear, why the minor ticks shouldn't work with a yearly frequency on the major ticks.

Comienza con la reproducción enlazada de CodePen y verifica la interacción entre yearly tickformat, ticklabelmode 'period' y minor ticks. Sigue los puntos de entrada de generación de ticks y del modo de etiquetas del eje para identificar por qué se omiten los minor ticks; el trabajo estará terminado cuando los minor ticks aparezcan con las tres propiedades habilitadas y los casos existentes sigan funcionando.