Agent Logging Level Automatically Resets to Default i.e Info After Upgrading Agents on an Upgraded Kibana Build

[kishorkumar-qasource]

• Agent Logging Level Automatically Resets to Default i.e Info After Upgrading Agents on an Upgraded Kibana Build #12949

Kibana Build details:

VERSION: 9.3.1 BC3
BUILD: 95740
COMMIT: 342266a63c5cedf139febf5a982ceb9a1c46690b

Preconditions:

1. Agents should be enrolled in 9.2.x.
2. The logging level of the agents should be set to either Debug, Warn, or Error on the 9.2.x build.
3. Kibana should be upgraded from 9.2.x to 9.3.1 BC3.

Steps to Reproduce:

1. Navigate to Assets > Agents tab.
2. Verify the logging level of the agent.
3. Navigate back to the Agents tab.
4. Click on the Action button of the same Agent.
5. Select Upgrade Agent and upgrade the agent to version 9.3.1 BC3.
6. Wait for the agent to upgrade.
7. Open Agent Details and observe the logging level of the agent has changed to Info, i.e., the default logging level.

Expected Result:

• Agent logging level should remain unchanged after upgrading the agent using an upgraded Kibana build.

Screen Capture:

1b.mp4

After Agent Upgrade

What's Working Fine:

• The logging level does not change when the agent upgrade is performed without upgrading the build.

without.upg.mp4

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[kishorkumar-qasource]

Hi @amolnater-qasource Kindly review this.

[amolnater-qasource]

Secondary review of this ticket is Done.

[cmacknz]

Can you try to reproduce now that #13289 has been merged?

The upgrade includes a restart, so I suspect this is the same underlying bug as #13196

[amolnater-qasource]

Hi @cmacknz  ,

We have revalidated this ticket by upgrading latest 9.3.3 SNAPSHOT to latest 9.4.0-SNAPSHOT Kibana cloud environment and found it  still reproducible.

Observations:

• After upgrading Kibana and the agent, the agent’s logging level automatically resets to the default (info).

Build Details:

VERSION: 9.3.3-SNAPSHOT
BUILD: 96242
COMMIT: 3efe5fae81ac26b17187fdbb6c9bd7059df06a53

VERSION: 9.4.0-SNAPSHOT
BUILD: 100301
COMMIT: b988bf3fa42b57c98a0a089dfaa580f5ff76dfe5

Screen Recording:

• Before Agent Upgrade

Screen.Recording.2026-04-08.at.5.44.42.PM.mov

• After Agent Upgrade

Screen.Recording.2026-04-08.at.5.46.39.PM.mov

Please let us know if anything else is required from our end.
Thanks!

[cmacknz]

Thanks, we also have a user report that when changing the log level from info to warning in the agent policy, it eventually goes back to info on its own.

So this may in fact be a different bug than #13196