At the end of the day, this was because the hardware ecosystem (and the hardware support in Linux/bootloaders/etc) isn't really "ready" yet, and also there was slow and unclear communications between the porting team, the core Debian teams and one of the hosting providers. Eventually the teams provisionally approved the port, but after that the needed actions weren't done in time for the archive-wide rebuild that happens during the process of an unofficial port becoming official. I'm not on the porting team, but am on the Debian sysadmin team, and tried to speed up the process and make it more transparent. Debian contributors are mostly volunteers, so things take time.