This is not a bug, it is expected & reasonable behaviour.
The `-p DIR' and `--tmpdir[=DIR]' mktemp(1) options
are the same, excepting that the argument is
mandatory for -p and optional for --tmpdir. (See
the manpage (`man mktemp') or try `mktemp --help'.)
That is, the following are equivalent:
Note: coreutils verions as shown by dpkg -l command:
$ dpkg -l coreutils
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version
