ERROR: The "x" line break is not justifying left

Question

I made a line break in the title of the "x" axis using the " n" and the break did not respect the horizontal justification on the left.

Follow the data:

> dput(PCLstack)
structure(list(Grupo = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L), .Label = c("TEPT", "TA", "TOC", "Controle"), class = "factor"), 
    ClusterB = c(9, 10, 12, 11, 17, 19, 11, 19, 16, 12, 14, 19, 
    13, 15, 14, 19, 18, 14, 14, 14, 15, 9, 14, 18, 14, 12, 14, 
    11, 18, 15, 18, 11, 13, 15, 20, 10, 15, 15, 9, 17, 18, 14, 
    14, 15, 15, 16, 15, 15, 16, 14, 13, 20, 11, 16, 15, 19, 15, 
    12, 18, 10, 19, 14, 14, 15, 18, 20, 13, 14, 16, 20, 14, 16, 
    18, 10, 16, 11, 2, 3, 6, 6, 6, 6, 2, 2, 6, 5, 7, 6, 4, 3, 
    5, 3, 8, 3, 8, 5, 6, 6, 2, 6, 6, 6, 6, 3, 5, 2, 5, 3, 4, 
    3, 3, 3, 5, 6, 1, 2, 4, 2, 6, 5, 4, 6, 5, 2, 4, 6, 3, 5, 
    6, 2, 3, 5, 5, 3, 5, 4, 3, 6, 1, 5, 6, 5, 5, 3, 4, 5, 4, 
    5, 3, 6, 6, 3, 3, 5, 9, 9, 9, 9, 9, 9, 9, 9, 8, 4, 5, 3, 
    3, 5, 3, 4, 5, 2, 4, 4, 4, 5, 5, 2, 5, 3, 5, 4, 6, 4, 8, 
    5, 6, 5, 4, 3, 3, 2, 6, 4, 3, 1, 4, 5, 3, 4, 6, 2, 1, 5, 
    5, 7, 3, 8, 5, 0, 4, 4, 6, 4, 3, 5, 8, 3, 5, 7, 6, 3, 5, 
    3, 5, 6, 5, 6, 1, 2, 6, 1, 2, 5, 1, 1, 6, 5, 6, 5, 6, 1, 
    2, 1, 5, 2, 2, 2, 5, 6, 5, 5, 5, 2, 5, 6, 5, 4, 1, 6, 6, 
    6, 2, 6, 1, 2, 2, 1, 5, 5, 6, 2, 6, 5, 5, 1, 5, 2, 5, 1, 
    5, 2, 2, 6, 6, 2, 5, 5, 2, 6, 6, 2, 6, 6, 2, 5, 5, 2)), row.names = c(NA, 
-298L), class = "data.frame")
> 

I used the following lines:

    require(ggplot2)
    require(ggpubr)
    require(ggsignif)

compar = list(c("TEPT","TA"),c("TEPT","TOC"),c("TEPT","Controle"),
              c("TA","TOC"),c("TA","Controle"),c("TOC","Controle"))

sigs <- c("p < 0,05","p < 0,01","p < 0,001","ns","ns","ns")

cores <- scale_fill_manual(values = c("red","yellow","#007eff","green"))

boxBstack <- ggplot(PCLstack, aes(Grupo, ClusterB),color = "black") +
  stat_boxplot(geom = "errorbar", size = 0.5, width = 0.1) +
  geom_boxplot(aes(fill = Grupo), show.legend = F) +
  labs(title = "Intrusão",
       x = expression(paste("Welch = 229,769; gl = 3, sig. = p < 0,001;\n", eta^2,"= 0,808")),
       y = "Escores") +
  theme(axis.text.x = element_text(size = 10, face = "bold", color = "Black"),
        axis.text.y = element_text(size = 10, color = "black"),
        plot.title = element_text(size = 12),
        axis.title.y = element_text(size = 10, face = "bold"),
        axis.title.x = element_text(size = 10,hjust = 0, vjust = 0)) +
  geom_signif(comparisons = compar,
              textsize = 2.8,
              margin_top =  c(.1,.2,.3,-.2,-.3,-.4),
              tip_length = c(0.1,0.03,
                             0.03,0.1,
                             0.1,0.03,
                             0.03,0.03,
                             0.03,0.03,
                             0.03,0.03),
              annotations = format(x = sigs)) +
  scale_y_continuous(limits = c(0,30),breaks = seq(0,30,5)) + cores

boxBstack

Watch the line break as it goes:

Where is the error?