ggplotly: Date displaying incorrectly on hover in plotly_3.1.0

[McClellandLegge]

The x-axis date in the below minimally reproducible example is being displayed incorrectly

devtools::install_github("ropensci/plotly")
library(ggplot2)
library(plotly)

x <- structure(list(end = structure(c(7029, 7120, 7212, 7304, 7394,
7485, 7577, 7669, 7759, 7850, 7942, 8034, 8125, 8216, 8308, 8400,
8490, 8581, 8673, 8765), class = "Date"), type = c("B", "A",
"B", "A", "B", "B", "B", "B", "A", "B", "A", "B", "A", "B", "B",
"A", "B", "B", "A", "B"), value = c(0.0567610084544867, 0.663610498653725,
0.609555944567546, 0.871052770875394, 0.356518815038726, 0.789101186208427,
0.723040267359465, 0.998758367961273, 0.483275642152876, 0.436393319396302,
0.0783511290792376, 0.551598326535895, 0.408145958557725, 0.518918534042314,
0.317269289400429, 0.208864476298913, 0.0491959238424897, 0.538105259882286,
0.552428187569603, 0.12881894572638)), .Names = c("end", "type",
"value"), class = c("data.table", "data.frame"), row.names = c(NA,
-20L))

ggplotly(p = ggplot(x, aes(end, value, colour = type)) + geom_line())

devtools::session_info()

Session info -------------------------------------------------------------------------
setting value
version R version 3.2.3 (2015-12-10)
system x86_64, mingw32
ui RStudio (0.99.879)
language (EN)
collate English_United States.1252
tz America/Chicago
date 2016-03-09

Packages -----------------------------------------------------------------------------------------------------
package * version date source
assertthat 0.1 2013-12-06 CRAN (R 3.2.3)
base64enc 0.1-3 2015-07-28 CRAN (R 3.2.3)
colorspace 1.2-6 2015-03-11 CRAN (R 3.2.3)
DBI 0.3.1 2014-09-24 CRAN (R 3.2.3)
devtools * 1.10.0.9000 2016-03-01 local
digest 0.6.8 2014-12-31 CRAN (R 3.2.2)
dplyr 0.4.3 2015-09-01 CRAN (R 3.2.3)
ggplot2 * 2.1.0 2016-03-01 CRAN (R 3.2.3)
gridExtra 2.2.1 2016-02-29 CRAN (R 3.2.3)
gtable 0.2.0 2016-02-26 CRAN (R 3.2.3)
htmltools 0.3 2015-12-29 CRAN (R 3.2.3)
htmlwidgets 0.6 2016-02-25 CRAN (R 3.2.3)
httr 1.1.0 2016-01-28 CRAN (R 3.2.3)
jsonlite 0.9.19 2015-11-28 CRAN (R 3.2.3)
magrittr 1.5 2014-11-22 CRAN (R 3.2.3)
memoise 1.0.0 2016-01-29 CRAN (R 3.2.3)
munsell 0.4.3 2016-02-13 CRAN (R 3.2.3)
packrat 0.4.6-1 2015-11-05 CRAN (R 3.2.3)
plotly * 3.1.0 2016-03-09 Github (bde1158)
plyr 1.8.3 2015-06-12 CRAN (R 3.2.3)
R6 2.1.2 2016-01-26 CRAN (R 3.2.3)
Rcpp 0.12.3 2016-01-10 CRAN (R 3.2.3)
rstudioapi * 0.3.1 2015-04-07 CRAN (R 3.2.2)
scales 0.4.0 2016-02-26 CRAN (R 3.2.3)
tidyr 0.4.1 2016-02-05 CRAN (R 3.2.3)
viridis 0.3.3 2016-03-04 CRAN (R 3.2.3)
withr * 1.0.1 2016-02-04 CRAN (R 3.2.3)