Comment 2 for bug 2063087

For reference.

Invalidation of cached remote unit settings for relation hook kinds (selective):
https://github.com/juju/juju/blob/f4a2a6605a6907eb40cf36133a5d419f7d4bd0f5/worker/uniter/runner/context/contextfactory.go#L268

Pruning of the cache members to those in the relation (all contexts):
https://github.com/juju/juju/blob/f4a2a6605a6907eb40cf36133a5d419f7d4bd0f5/worker/uniter/runner/context/contextfactory.go#L357

The latter of which always clears application settings in the cache, causing a fetch from the controller upon first access:
https://github.com/juju/juju/blob/f4a2a6605a6907eb40cf36133a5d419f7d4bd0f5/worker/uniter/runner/context/cache.go#L57