Yes, this is the wanted behaviour and no, there is no option for that.
Seems like your server (whichever it is) is returning the incorrect path
/user/cal (instead of
/dir/user/cal) to DAVdroid.
Thanks - and you are correct! DavDroid uses the path returned from the server root to dictate where to put the relative path on PROPFIND calls - changing it to dir/ results in it working fine. Great app.