Comment 2 for bug 1950835

Thanks for the hint about `refresh` John.

In this case the upgrade did not go straight to 2.9 and the environment was upgraded to 2.7 and 2.8 in between. Both controller and model were upgraded in each step. The issue with the nrpe charm was only discovered though when trying to upgrade the charm using juju 2.9. In other words, we don't know when that information you mention went missing.