If I have an /etc/network/interfaces file like the below, when the system gets rebooted, only eth0 and eth0:0 are created, eth0:1 never gets created.

This seems to be a bug of some sort ?

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
        address 192.0.2.30
        netmask 255.255.255.0
        broadcast 192.0.2.255
        gateway 192.0.2.250

auto eth0:0
iface eth0:0 inet static
        name Foo
        address 192.0.2.31
        netmask 255.255.255.0
        broadcast 192.0.2.255

auto eth0:1
iface eth0:1 inet static
        name  Bar
        address 192.0.2.32
        netmask 255.255.255.0
        broadcast 192.0.2.255

(from redmine: issue id 10206, created on 2019-04-07)