The monitoring settings below are currently validated at usage time meaning that they can be accepted into the cluster state when invalid thereby poisoning the cluster state with the invalid setting. All of the following should be validated as part of the settings validation framework which will eliminate this problem.

• AUTH_USERNAME_SETTING (Validate monitoring username at parse time #47821)
• PROXY_BASE_PATH_SETTING (Validate proxy base path at parse time #47912)
• HEADERS_SETTING (Validate monitoring header overrides at parse time #47848)
• INDEX_NAME_TIME_FORMAT_SETTING (Validate index name time format setting at parse time #47911)
• AUTH_PASSWORD_SETTING (Validate monitoring password at parse time #47740)
• SSL_SETTING (Validate SSL settings at parse time #49196)

This should resolve all of the instances of the problem described in #47038 for settings related to monitoring.