theme_af() does not inherit base_size from use_afcharts()

[fingertipsy]

When proving style defaults in use_afcharts(), such as use_afcharts(base_size = 40), I would expect that after calling this function all ggplot objects inherit those styles.

Normally this is the case, for example:

use_afcharts(base_size = 40)

gapminder |>
filter(country %in% c("United Kingdom", "China")) |>
ggplot(aes(x = year, y = lifeExp, colour = country)) +
geom_line(linewidth = 1)

However, it is not the case if the ggplot has an af_theme() layer, for example:

use_afcharts(base_size = 40)

gapminder |>
filter(country %in% c("United Kingdom", "China")) |>
ggplot(aes(x = year, y = lifeExp, colour = country)) +
geom_line(linewidth = 1) +
theme_af(legend = "bottom")

If there is an af_theme() layer, the base_size style set in use_afcharts() is overwritten. Is this intended behaviour?