wrong stats in GTiff files made with writeRaster() (through rgdal?)

I've just noted that files created with writeRaster() have wrong stats
(which is a problem later in Qgis, for example).
Not sure if writeRaster() uses rgdal, in that case the problem might
be more general:

delme <- subset(adlstest,c("B48","B31","B21"))
summary(delme)

Cells:  1089
NAs  :  0 0 0

           1    2    3
Min.    2563 3491 3822
1st Qu. 2700 3636 3971
Median  2764 3691 4009
Mean    2781 3699 4014
3rd Qu. 2862 3765 4055
Max.    3629 3979 4258

GDALinfo("delme.tif")

rows        33
columns     33
bands       3
origin.x        648490.8
origin.y        7058623
res.x       29.9746
res.y       29.99077
ysign       -1
oblique.x   0
oblique.y   0
driver      GTiff
projection  +proj=utm +zone=19 +south +datum=WGS84 +units=m +no_defs
file        delme.tif
apparent band summary:
   GDType Bmin Bmax Bmean Bsd hasNoDataValue NoDataValue
1 Float32 2563 3629     0   0           TRUE           0
2 Float32 3491 3979     0   0           TRUE           0
3 Float32 3822 4258     0   0           TRUE           0
Metadata:
AREA_OR_POINT=Area

Note the 0 means and sd !

adlstest here:
http://dl.dropbox.com/u/3180464/adlstest.rda

Agus

sessionInfo()

R version 2.15.1 (2012-06-22)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
LC_MONETARY=en_US.UTF-8
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=C                 LC_NAME=C
               LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

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

other attached packages:
[1] rgdal_0.7-5   raster_2.0-08 sp_0.9-99

loaded via a namespace (and not attached):
[1] grid_2.15.1     lattice_0.19-30 tools_2.15.1