I tried to reproduce the issue and am not able to.
I used the following code to make a reproducible example and simply created the data frame with the resulting data you're showing:
s <- data.frame(tgt = c(1094, 1087, 1260, 1646, 2204, 2096, 1896, 1988, 1776, 1897, 1321, 1199),
whole = c(9598, 8675, 9335, 9680, 13467, 12798, 13724, 13646, 10770, 11463, 10418, 9270))
boxplot(s)
This worked fine with no errors:
Interestingly, summary(s) returned slightly different results from what you show in your post:
tgt whole
Min. :1087 Min. : 8675
1st Qu.:1245 1st Qu.: 9532
Median :1711 Median :10594
Mean :1622 Mean :11070
3rd Qu.:1920 3rd Qu.:12965
Max. :2204 Max. :13724
This has me wondering if there is something in your data that is not quite as it is represented in your question that is causing the issue?