theme_solarized warnings

[mdodrill-usgs]

theme_solarized in the latest version of ggthemes (4.0.0) with R version 3.5.1 throws warnings and does not seem to display the solarized theme correctly. Example below:

library(ggplot2)
library(ggthemes)

windows()

dat = data.frame(x = 1:10,
y = 1:10)

p = ggplot(dat, aes(x = x, y = y)) +
geom_point()

p

p + theme_solarized()

sessionInfo()
R version 3.5.1 (2018-07-02)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C LC_TIME=English_United States.1252

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] ggthemes_4.0.0 ggplot2_3.0.0

loaded via a namespace (and not attached):
[1] Rcpp_0.12.18 rstudioapi_0.7 bindr_0.1.1 magrittr_1.5 tidyselect_0.2.4 munsell_0.5.0 colorspace_1.3-2 R6_2.2.2
[9] rlang_0.2.2 stringr_1.3.1 plyr_1.8.4 dplyr_0.7.6 tools_3.5.1 grid_3.5.1 gtable_0.2.0 withr_2.1.2
[17] yaml_2.2.0 lazyeval_0.2.1 assertthat_0.2.0 tibble_1.4.2 crayon_1.3.4 bindrcpp_0.2.2 purrr_0.2.5 glue_1.3.0
[25] labeling_0.3 stringi_1.2.4 compiler_3.5.1 pillar_1.3.0 scales_1.0.0 pkgconfig_2.0.2