for those of you who do have the same update problems with
- pamac-aur and
- pamac-tray-appindicator
In a comment to the package details of pamac-aur on archlinux.org it is adviced to install 'asciidoc'.
After the install of asciidoc 'pamac-aur' updated now fine but a message that 'pamac-tray appindicator' is in conflict with '/etc/xdg/autostart/pamac-tray.desktop' and '/usr/xdg/pamac-tray' did now poped up.. So before removing these files I first did renamed these files and than did run the update again. Now the update did run without any error or conflict messages and at least than I did delete the renamed files.