Looks to me like this would be an issue caused by remaining files from other iso images when they are done using usb-creator.
If you're running into the server install failing with such errors as "busybox-initramfs" failing to install or other messages saying that "apt-install or in-target are already in use"; see if you have a stray "casper" directory on the USB drive used to do the install.
This would happen for people writing a desktop image to a USB drive, then writing a server image without formatting; the base installer will pick the squashfs file from casper/ first if it's there, which could make the installation fail.
Looks to me like this would be an issue caused by remaining files from other iso images when they are done using usb-creator.
If you're running into the server install failing with such errors as "busybox-initramfs" failing to install or other messages saying that "apt-install or in-target are already in use"; see if you have a stray "casper" directory on the USB drive used to do the install.
This would happen for people writing a desktop image to a USB drive, then writing a server image without formatting; the base installer will pick the squashfs file from casper/ first if it's there, which could make the installation fail.