The problem happens due to prematurely removing the 1.18 compatibility code in https://github.com/juju/juju/pull/308, more specifically in this commit https://github.com/juju/juju/commit/515715ccc71cec662625caef7eba60a97c6b9e80.
The solution is to reintroduce the compatibility code.
The problem happens due to prematurely removing the 1.18 compatibility code in https:/ /github. com/juju/ juju/pull/ 308, more specifically in this commit https:/ /github. com/juju/ juju/commit/ 515715ccc71cec6 62625caef7eba60 a97c6b9e80.
The solution is to reintroduce the compatibility code.