Comment 3 for bug 1870134

It turns out that the pip, setuptools, and setuptools-scm bundling in layer:basic ends up downgrading these packages on Focal causing this issue, but only after the initial bootstrap. Flannel seems to run an upgrade-charm during the initial install for some reason, which is why we're seeing this on this charm and not others, but it will affect all reactive charms on Focal at the first upgrade.

I filed this against layer:basic at https://github.com/juju-solutions/layer-basic/issues/159 and have a PR in progress to address this at https://github.com/juju-solutions/layer-basic/pull/160