There are some users reported issues install new snap after fresh install of Ubuntu Desktop 18.04 or 19.04. It seems to me they are all caused by the same snapd issue.
The seeded snap in a Desktop image will pull the latest snap based on a list of names in live-build config. If a developer builds a new bionic image today without upgrading the pre-seeded snap names, the image will end up shipping a new gnome-* snap (eg: gnome-calculator) depends on new gnome-3-28-1804.
Since only gnome-3-26-1604 is pre-seeded, snapd never able to solve the prerequisites of the new gnome-calculator. So “Initialize system state” task never gets done. When a user trying to install a new snap, the snapd will complain “too early for operation, device not yet seeded or device model not acknowledged”
When the users have the issue, they need to manually edit /var/lib/snapd/seed/seed.yaml and restart snapd and seeding to fix the dependency issue.
There is a similer issue when the pre-seed content snap does not have the right order, which blocking snapd to finish the initialization.
Should snapd ignore the broken dependency for seeding by just install the snap without the content snap? At least not blocking a user to solve the issue by installing a required snap.
 Bug #1826662 “Can’t install any snaps: too early for operation, …” : Bugs : snapd - https://bugs.launchpad.net/bugs/1826662
 software installation - Snaps won’t install in Ubuntu 18.04 - Ask Ubuntu - https://askubuntu.com/questions/1107388/snaps-wont-install-in-ubuntu-18-04
 software installation - Ubuntu 18.04 LTS: too early for operation error - Ask Ubuntu - https://askubuntu.com/questions/1114117/ubuntu-18-04-lts-too-early-for-operation-error
 Ubuntu Software won’t let me download anything. : linux4noobs - https://www.reddit.com/r/linux4noobs/comments/a97q6h/ubuntu_software_wont_let_me_download_anything/
 gnome - The image from quick create in hyper-v for Ubuntu 18.04.2 doesn’t allow me to install anything - Ask Ubuntu - https://askubuntu.com/questions/1144072/the-image-from-quick-create-in-hyper-v-for-ubuntu-18-04-2-doesnt-allow-me-to-in/1144449#1144449
 Bug #1772844 “snapd didn’t initialize all the seeded snaps” : Bugs : ubuntu-meta package : Ubuntu - https://bugs.launchpad.net/bugs/1772844