sudo password prompt timeout not working as expected

Hi,

On my orangepi zero (256MB) running armbian image, I am observing some odd behavior that I do not fully understand.

Linux sinaspi 5.10.16-sunxi #21.02.2 SMP Sun Feb 14 21:12:17 CET 2021 armv7l GNU/Linux

Distributor ID: Debian
Description:    Debian GNU/Linux 10 (buster)
Release:        10
Codename:       buster

In an effort to 'harden' the orangepi zero configuration (by making the user experience annoying), I have shortened the sudo password prompt timeout. On the orangepi zero board, the following setting results in a timeout of only 2 seconds, instead of 15 seconds:

#[BEGIN] Ansible managed
## DMZ special: Authentication always required except for TOOLS
djurny ALL = (root) PASSWD: ALL, NOPASSWD: TOOLS

## DMZ special: Stricter timeout settings
Defaults:djurny passwd_timeout=0.25
Defaults:djurny timestamp_timeout=0

Defaults:djurny !logfile
Defaults:djurny !syslog
#[END]

The exact same setting works as expected on raspberrypi and also as expected on nanopi R2S (armbian). Even more odd, setting the timeout to 1, the timeout is indeed set to 1 minute. Setting it to any fractional value like 0.3 or 0.5 it seems that the timeout calculation/interpretation is just not working as per manpage.

I'm not blocked by this, but if this is something that can be fixed easily, I will. For now, I've just the timeout to 1 minute (still more annoying than 15 minute timeout :-)

Anyone have experienced this as well?

Groetjes,