Comment 6 for bug 1821418

I'm able to reproduce this simply in a lab on LXD provider:

sudo snap refresh juju --channel 2.4/stable
juju bootstrap localhost lxd --config config.yaml
juju deploy ubuntu
juju export-bundle > ./bundle24.yaml
juju deploy --dry-run ./bundle24.yaml (result is "no changes to apply")
sudo snap refresh juju --channel 2.5/stable
juju deploy --dry-run ./bundle24.yaml (result is "no changes to apply")
juju upgrade-model -m controller; sleep 300
juju deploy --dry-run ./bundle24.yaml (result is "ERROR cannot deploy bundle: connection is shut down")
juju export-bundle > ./bundle25.yaml
juju deploy ./bundle25.yaml (result is "ERROR cannot deploy bundle: connection is shut down")

no diff between the bundle24/25.yaml files, it seems the error is on the controller upgrade from 2.4 to 2.5.

config.yaml contents:

default-series: xenial
apt-http-proxy: http://10.0.8.1:8000