CentOS - May 2020 - Centos8.1 Plymouthd crash 913: ply_event_loop_watch_for_timeout: Assertion `seconds > 0.0' failed.

Hi,

I?m running a special initrd generated for SystemImager with a special dracut
module that relies on plyouth scripted theme.
It works perfectly on CentOS-6, CentOS-7, OpenSUSE-42.3, Fedora-29 (not tested
later) and used to work on CentOS-8.0

Since CentOS-8.1 was released, IT chrashes with the following error:
Plymouthd crash 913: ply_event_loop_watch_for_timeout: Assertion `seconds >
0.0' failed.

I?m running quemu 5.0.0 with tianocore UEFI bios on MacOS (using accel=none or
accel=hvf) (Bug also occurs with standard 256k bios)

When I strace, I see multiple reasons but I can?t tell wich one is fatal.
1/ plymouthd reads /etc/Plymouth/plymouthd.conf (ok), then tries to read them
from /var/run/plymouth/themes/<themename> instead of
/usr/share/plymouth/themes/<themename>/ . As it fails it tries to read
/var/run/plymouth/plymouthd.defaults (fails) then
/usr/share/plymouth//plymouthd.defaults (ok) then it tries to read the theme
/var/run/plymouth/themes/<themename>/<themename>.plymouth (fails)
but never tries to read in from
/usr/share/plymouth/themes/<themename>/<themename.plymouth> ???

It still continues

2/ After a few things, it tries to read /sys/devices/virtual/drm/ttm/uevent (ok)
and the it tries to read /run/dev/data/+drm:ttm (fail). Is it expectable or does
this means a problem like a missing udev rule or a boch driver bug or something
else?

3/ Same as step 2

4/ Crash with @lymouthd: ply-event-loop.c:913: ply_event_loop_watch_for_timeout:
Assertion `seconds > 0.0' failed.

I?ve reported this in Centos-8.1 with no return and then RedHat-8.1 today.
RedHat 8.1 bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1836828
CentOS-8.1 bug report: https://bugs.centos.org/view.php?id=17140

Any idea where I could look for? More likely a plymouth bug or an udev missing
rule or something else?
(full dmesg and strace log in bug reports)

Thanks a lot for any tips.

PS: looking at google results, the only things I can find are very old bugs
without resolution (not fixed and obsoleted due to new OS release)

-- 
Olivier LAHAYE