R terra resample always returns floating min of -3.4e+38

i am using terra::raster 0.9-1 and, specifically terra::resample, but whenever i resample/reproject a surface, i get what appears to be the minimum floating point value as the default fill/NA value

> sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)
other attached packages:
 [1] terra_0.9-1       gdalUtils_2.0.3.2 geosphere_1.5-10  data.table_1.13.0 ggplot2_3.3.2     dplyr_1.0.2      
 [9] rgdal_1.5-16      rgeos_0.5-3       stringr_1.4.0     raster_3.3-13     sp_1.4-4          devtools_2.3.1


# as i cannot make a dummy rast, due to being unable to set values, you'll have to take my word for it
# https://gis.stackexchange.com/questions/377839/r-terra-and-error-in-xptrgeometrynlyrs-could-not-find-valid-method

r <- rast("C:/Path/BNG_raster.tif")
crs(r) <- "epsg:27700"

latlon.grid <- rast(xmin = 0, xmax = 5, ymin = 50, ymax = 55, resolution = 0.01, crs = "epsg:4326", vals = NA)

r.resam <- terra::resample(r, latlon.grid, method="cubic")

> r.resam
class       : SpatRaster 
dimensions  : 50, 50, 1  (nrow, ncol, nlyr)
resolution  : 0.01, 0.01  (x, y)
extent      : 0, 5, 50, 55  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +no_defs 
data source : memory 
names       : my_reprojected_raster 
min values  :                                         -3.4e+38 
max values  :                                         95.97936 

you can see the min value defaults to the minimum floating point value. The following do not change that;

terra::resample(r, uk.latlon.grid.wkt, method="cubic", background=NA)
terra::resample(r, uk.latlon.grid.wkt, method="cubic", wopt=list(NAflag=NA))
terra::resample(r, uk.latlon.grid.wkt, method="cubic", wopt=list(NAflag=0))

That in itself is ok but then subsequent raster algebra operations recognize the -3.4e+38 as a value. Is there a best practice for dealing with NA in terra? i was used to raster in which NA was just NA.

the best result i have is to write out at the raster at the same time (similar to gdalwarp);

test <- terra::resample(r, uk.latlon.grid.wkt, method="cubic", filename="E:/samT/dump/eire_S3_LL_terra.tif", wopt=list(NAflag=NA), overwrite=T, wopt=list(gdal=c("COMPRESS=LZW")))

> test
    class       : SpatRaster 
    dimensions  : 50, 50, 1  (nrow, ncol, nlyr)
    resolution  : 0.01, 0.01  (x, y)
    extent      : 0, 5, 50, 55  (xmin, xmax, ymin, ymax)
    coord. ref. : +proj=longlat +datum=WGS84 +no_defs 
    data source : memory 
    names       : my_reprojected_raster 
    min values  :                                         -5.59 
    max values  :                                         95.97936