Accidental serial compatibility mistakes like the one described in https://github.com/jenkinsci/hashicorp-vault-plugin/issues/326 should be limited in extent to the closest surrounding RobustFooConverter, which should report the warning to OldDataMonitor but otherwise ignore the broken element and continue deserialization normally.

In that issue, a mistake involving a Map field in a folder property lead to the folder itself being corrupted in a way that caused further problems, which we would like to avoid.

https://github.com/jenkinsci/jenkins/pull/9653 proposes a change to RobustMapConverter which would have limited the impact of this kind of mistake.