Comment 1 for bug 1975678

This seems to be due to the (old) Python YAML parser being in conflict with libnetplan's actual C YAML parser.

Apparently pyyaml interprets "off" as a boolean ('False') by default in yaml.safe_load(value) (`set_tree = self.parse_key(key, yaml.safe_load(value))`), while it is supposed to be an actual string ("off") for activation-mode.

Looks like it was broken ever since netplan set was introduced (v0.101) and just recently got fixed via https://github.com/canonical/netplan/pull/254 (https://github.com/canonical/netplan/commit/bdb4f9846c8f40275c09a28bed04d8436cbbeffc to be specific)