Comment 3 for bug 2045317

If there were no other series/base and/or arch constraints in place that would otherwise exclude that sole charm, then you'd expect Juju could pick that one all other things being equal.

Note that there's a model config item called "default-base" which can be set, and if that's not set, Juju falls back to 22.04 as being the base to use if not specified. So that's why I think Juju did not select that 20.04 charm. That's why you need to include base in the bundle.

So I think it still comes back to the error message being a bit rubbish.