Bug when using horizontal stacking for plots with theme(strip.placement = "outside")

[gbiele]

If one tries to stack two plots patchwork and one of the plots uses facet_grid and theme(strip.placement = "outside"), this messes up the placement of tick marks.

Minimal reproducible example

The following works as expected:

df = 
  data.frame(
  inc = rep(1:10,3),
  prev = rnorm(30),
  grp = rep(c("a","b","x"),each=10)
)

p1 = ggplot(df,aes(x = inc, y = prev, color = grp)) + geom_point()

p2.a = ggplot(df,aes(x = inc, y = prev, color = grp)) + 
  geom_point() + 
  facet_grid(~grp) 

p1 / p2.a

Now modify plot p2.a and stack again:

p2.b = p2.a + theme(strip.placement = "outside")
p1 / p2.b

In the second plot, y-ticks marks and labels and y-label of the top plot are be moved to the right, so that the y-tick labels of the top plot are horizontally aligned with the y-label of the bottom plot. See also this figure.

Note: For this minimally reproducible example theme(strip.placement = "outside") does not change the plot. In my application I need theme(strip.placement = "outside") to manage the position of tick marks after using scale_y_continuous(sec.axis = dup_axis()), which I have omitted from the example.