I'm not sure if this is intentional but doesn't seem like it should be. Looks like forderv is probably the culprit.
library(data.table)
x <- c(0, Inf)
unique(data.frame(x))
#> x
#> 1 0
#> 2 Inf
unique(data.table(x))
#> x
#> 1: 0
unique(data.table(c(x, 1)))
#> V1
#> 1: 0
#> 2: Inf
#> 3: 1
devtools::session_info()
#> - Session info ----------------------------------------------------------
#> setting value
#> version R version 3.5.2 (2018-12-20)
#> os Windows 7 x64 SP 1
#> system x86_64, mingw32
#> ui RTerm
#> language (EN)
#> collate English_United States.1252
#> ctype English_United States.1252
#> tz America/New_York
#> date 2019-02-07
#>
#> - Packages --------------------------------------------------------------
#> package * version date lib
#> assertthat 0.2.0 2017-04-11 [1]
#> backports 1.1.3 2018-12-14 [1]
#> callr 3.1.1 2018-12-21 [1]
#> cli 1.0.1 2018-09-25 [1]
#> crayon 1.3.4 2017-09-16 [1]
#> data.table * 1.12.1 2019-02-07 [1]
#> desc 1.2.0 2018-05-01 [1]
#> devtools 2.0.1 2018-10-26 [1]
#> digest 0.6.18 2018-10-10 [1]
#> evaluate 0.12 2018-10-09 [1]
#> fs 1.2.6 2018-08-23 [1]
#> glue 1.3.0 2018-07-17 [1]
#> highr 0.7 2018-06-09 [1]
#> htmltools 0.3.6 2017-04-28 [1]
#> knitr 1.21 2018-12-10 [1]
#> magrittr 1.5 2014-11-22 [1]
#> memoise 1.1.0 2017-04-21 [1]
#> pkgbuild 1.0.2.9000 2019-02-07 [1]
#> pkgload 1.0.2 2018-10-29 [1]
#> prettyunits 1.0.2 2015-07-13 [1]
#> processx 3.2.1 2018-12-05 [1]
#> ps 1.3.0 2018-12-21 [1]
#> R6 2.3.0 2018-10-04 [1]
#> Rcpp 1.0.0 2018-11-07 [1]
#> remotes 2.0.2 2018-10-30 [1]
#> rlang 0.3.1 2019-01-08 [1]
#> rmarkdown 1.11 2018-12-08 [1]
#> rprojroot 1.3-2 2018-01-03 [1]
#> sessioninfo 1.1.1 2018-11-05 [1]
#> stringi 1.2.4 2018-07-20 [1]
#> stringr 1.3.1 2018-05-10 [1]
#> testthat 2.0.1 2018-10-13 [1]
#> usethis 1.4.0 2018-08-14 [1]
#> withr 2.1.2 2018-03-15 [1]
#> xfun 0.4 2018-10-23 [1]
#> yaml 2.2.0 2018-07-25 [1]
#> source
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> Github (Rdatatable/data.table@4cf5f45)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> Github (r-lib/pkgbuild@6e4ebdf)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#> CRAN (R 3.5.2)
#>
#> [1] C:/Program Files/R/R-3.5.2/library
```R
I'm not sure if this is intentional but doesn't seem like it should be. Looks like
fordervis probably the culprit.