The problem occurs using GRASS 7.8 but NOT using 7.6. Likewise, there is
no problem under Linux, only Windows 10.It might be related to some Windows environmental variables, but I don't
have a clue which ones. As the older version works, I wonder if it is
due to any changes from GRASS 7.6 to 7.8. Could anybody give me a hint?
QGIS bundled GRASS here:
GRASS Version: 7.8.5
Code revision: 2b6ab2893
Build date: 2020-12-21
Build platform: x86_64-w64-mingw32
GDAL: 3.1.4
PROJ: 6.3.2
see https://github.com/rsbivand/rgrass7/issues/27
it may be a mismatch between the GRASS bundled proj version and the R spatial packages bundled proj version.
please check the proj version in GRASS and R.
kind regards
Helmut