I check the permission and ownership of the files in the sda5 tar ball, they are not correct.
In principle this should be no problem as most of them are reset during boot, but maybe I overlooked one.
I updated the the autoinstall package in the download section with the an updated sd5 tar ball with permission set as they should be
please retry it if now the second boot is no longer necessary
ps I changed the name of the package by adding an "a" at the end of the name to be able to distinguish the different packages. The file names inside the packages are the same
I attached the new tar ball also to this post