I just upgraded leap 15.4 to leap 15.5 via dup

1) After upgrade  I noticed that many of the old-15.4 [ running fine] settings 
in the new system fail/crash .
journalctl -a | grep autostart  shows the culprit : 
systemd-xdg-autostart-generator  
yast points to systemd that is at level 249.16-150400.8.257 
which is NOT at level 15.5  !

Why leap 15.5 is using systemd 15.4 ?

2) Similar issue is with the QuickLunch service/application 
Some of the old [ 15.4 ] settings fail with these messages :
  a)
     Plasma Desktop Workspace
     Plasma Workspace 
     Could not find the program konsole [ or other system commands]
     Note-- it happens for many other command or bash shells 

   b) 
     Plasma Desktop Workspace
     Plasma Workspace 
     execvp : Exec format error 

I noticed these issues during the first 2 days of using the new leap 15.5 
here are the levels [ reported by yast ]
systemd  249.16-150400.8.25.7 
plasma5-desktop 5.27.4-bp155.1.7  
plasma-workspace 5.27.4.1-bp155.1.7

Please find below journalctl output ....
sudo journalctl -a | grep /home/<userid>/.config/autostart
Oct 07 08:29:27 <user-domain>.dom systemd-xdg-autostart-generator[5580]: /home/<userid>/.config/autostart/ org.kde.kontact.desktop:13: Unknown key name 'SingleMainWindow' in section 'Desktop Entry', ignoring.
Oct 07 08:29:27 <user-domain>.dom systemd-xdg-autostart-generator[5580]: /home/<userid>/.config/autostart/org.kde.kontact.desktop:16: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:29:27 <user-domain>.dom systemd-xdg-autostart-generator[5580]: /home/<userid>/.config/autostart/pia-client.desktop:14: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:29:27 <user-domain>.dom systemd-xdg-autostart-generator[5580]: /home/<userid>/.config/autostart/Start_Commands_for_autostart.desktop:14: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:29:27 <user-domain>.dom systemd-xdg-autostart-generator[5580]: /home/<userid>/.config/autostart/org.kde.kwalletmanager5.desktop:9: Unknown key name 'InitialPreference' in section 'Desktop Entry', ignoring.
Oct 07 08:30:12 <user-domain>.dom systemd-xdg-autostart-generator[7718]: /home/<userid>/.config/autostart/org.kde.kontact.desktop:13: Unknown key name 'SingleMainWindow' in section 'Desktop Entry', ignoring.
Oct 07 08:30:12 <user-domain>.dom systemd-xdg-autostart-generator[7718]: /home/<userid>/.config/autostart/org.kde.kontact.desktop:16: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:30:12 <user-domain>.dom systemd-xdg-autostart-generator[7718]: /home/<userid>/.config/autostart/pia-client.desktop:14: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:30:12 <user-domain>.dom systemd-xdg-autostart-generator[7718]: /home/<userid>/.config/autostart/Start_Commands_for_autostart.desktop:14: Unknown key name 'TerminalOptions' in section 'Desktop Entry', ignoring.
Oct 07 08:30:12 <user-domain>.dom systemd-xdg-autostart-generator[7718]: /home/<userid>/.config/autostart/org.kde.kwalletmanager5.desktop:9: Unknown key name 'InitialPreference' in section 'Desktop Entry', ignoring.
Oct 07 08:37:18 <user-domain>.dom systemsettings[9244]: kf.kio.core: Url QUrl("file:///home/<userid>/.config/autostart/org.kde.krusader.desktop") already represents a local file, cancelling job.
Oct 07 08:37:43 <user-domain>.dom systemsettings[9244]: kf.kio.core: Url QUrl("file:///home/<userid>/.config/autostart/org.kde.kontact.desktop") already represents a local file, cancelling job.
Oct 07 08:39:09 <user-domain>.dom systemsettings[9344]: kf.kio.core: Url QUrl("file:///home/<userid>/.config/autostart/org.kde.kontact.desktop") already represents a local file, cancelling job.