Comment # 7 on bug 1162511 from Freek de Kruijf

(In reply to Nicolas Patricio Saenz Julienne from comment #6)
> (In reply to Freek de Kruijf from comment #4)
> > The following USB devices are plugged in:
> > WiFi dongle (when unplugging the messages went on)
> > keyboard
> > mouse
> 
> Does the issue persist if booted without he WiFi dongle?

It did persist.

Currently I started all over again with XFCE for RPi4 for Tumbleweed with the
latest image:
openSUSE-Tumbleweed-ARM-XFCE-raspberrypi4.aarch64-2020.01.30-Snapshot20200201.raw.xz
I replaced packet wpa_supplicant by a lower version that I saved earlier.
Before first boot I reconfigured the SD card, removed swap partition, moved
partition ROOT to the left and enlarged it to 30G, made an 80G HOME and a 4G
swap. It is a 128GB SD card.
The WiFi interfaces, build-in and dongle, do not start during boot, but do come
up using "wicked ifup wlxxx".
Until now there is no flooding.
I hope to continue configuring the system tomorrow; postfix, dovecot,
thunderbird, and other user applications; also testing the XFCE desktop. I need
to do other things first.