legend.key.spacing change the distance between the key and the label

Hi!
Currently ggplot provides identity-detailed options for adjusting the properties of each element of the legend. The following options for legend.key.spacing{x/y}, which adjusts the distance of each mini group, and legend.text both work as expected.
ggplot2 3.5.0: Legends - Spacing and margins

(p <- ggplot(mpg, aes(displ, hwy, colour = class)) +
  geom_point() +
  guides(colour = guide_legend(ncol = 2)) 
)

p+  
  theme(
    legend.key.spacing.x = unit(20, "pt"))

But I have a doubt about the legend.key.spacing:

p+
  theme(legend.key.spacing = unit(20, "pt"))

From the result, it looks like the key and label spacing has changed. As legend.text = element_text (margin = margin (l = ...)) has been changed.

Should the distance between key and label change when using legend.key.spacing? I'm not quite sure if this is an intentional feature or a bug.

Best wishes,
Hu

Reproduce the two examples from the issue, using the linked ggplot2 3.5.0 spacing documentation as context. Trace the legend layout and theme handling that determine the distance between keys and labels. Done means establishing whether legend.key.spacing is intended to affect that distance and, if it is a bug, adding a focused regression test and correcting the documented behavior.