Welcome to the forums Juergen !
That is weird. Is this a direct installation on the machine or did you migrate an installation to it?
Originally Posted by Juergen_Singer
Does Network Manager show any wireless connections in its settings (NM drop-down menu > Edit Connections > Wireless tab)? Delete if there are any. If not, or if it gets re-created, please post back the following outputs -
Also, as soon as the machine comes back from sleep and starts trying to connect, run and post the outputs of -
lspci -nnk | grep -iA2 net
cat /var/log/syslog | egrep -i 'network|wlan' | tail -40