installing core snap from old snapd deb says "latest/stable is closed"

With an old snapd deb such as 2.37 which is currently in the bionic-security pocket, and can be installed with

sudo apt install snapd=2.37.4+18.04.1

I then tried to install the core snap:

ubuntu@credible-quetzal:~$ sudo snap install core
2020-06-05T05:55:30-05:00 INFO Waiting for restart...
core 16-2.45 from Canonical✓ installed
Channel latest/stable for core is closed; temporarily forwarding to stable.

The last message is quite confusing as a user, since the core snap does not have any tracks other than latest.