It is also possible to 'juju resolved --no-retry' the unit until the original upgrade-charm hook has had a chance to run, but this would still be better resolved by 'juju upgrade-charm --force-units' doing what it is told and forcing an upgrade onto the units.
It is also possible to 'juju resolved --no-retry' the unit until the original upgrade-charm hook has had a chance to run, but this would still be better resolved by 'juju upgrade-charm --force-units' doing what it is told and forcing an upgrade onto the units.