subplot - merging titles following ggplotly conversion

data(faithful)

p1 <- plotly::ggplotly(
  ggplot(faithful, aes(x = eruptions)) + 
    geom_histogram(bins = 20) + 
    theme_minimal()  + 
    labs(title = "A.")
)

p2 <- plotly::ggplotly(
  ggplot(faithful, aes(x = waiting)) + 
    geom_histogram(bins = 20) + 
    theme_minimal()  + 
    labs(title = "B.")
)

pl <- subplot(p1, p2, nrows = 1, titleX = TRUE)

## note  that changing to labs(tag = "A.") results in loss of the 'tag' at the ggplotly function.  

I am creating a gglot (histogram, in this case) which includes a sub-panel label. I want to then convert to a plotly figure using the plotly::ggplotly function. The label is transmitted faithfully to each of p1 and p2. However, when combining these into a subplot, the label seems to be merged . I lose the 'A.' label on the first plot p1, generally. The titleX option does not prevent this from occurring.

Comienza con el ejemplo reproducible de datos faithful usando ggplotly y subplot, y luego sigue cómo subplot combina los títulos de p1 y p2 cuando titleX está habilitado. Confirma el comportamiento para labs(title = "A.") y labs(title = "B."); se considera terminado cuando ambas etiquetas sigan visibles después de la conversión y la combinación.