[CI] ServerSentEventsRestActionListenerTests testResponse failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #4079 / rhel-9_platform-support-unix
• elasticsearch-intake #9818 / part2

Reproduction Line:

./gradlew ":x-pack:plugin:inference:internalClusterTest" --tests "org.elasticsearch.xpack.inference.rest.ServerSentEventsRestActionListenerTests.testResponse" -Dtests.seed=619704BF15AE6FA -Dtests.locale=cgg-UG -Dtests.timezone=America/Dawson -Druntime.java=22

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: No exceptions should be thrown.
Expected: null
     but: was <java.io.IOException: Line does not match expected JSON message or DONE message. Line: event: message
data: {"delta":"\uDBD2\uDE9BzＬ㟙�裦㘻\u0019"}>

Issue Reasons:

• [main] 2 failures in test testResponse (4.3% fail rate in 46 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

This has been muted on branch main

Mute Reasons:

• [main] 2 failures in test testResponse (4.3% fail rate in 46 executions)

Build Scans:

• elasticsearch-periodic-platform-support #4079 / rhel-9_platform-support-unix
• elasticsearch-intake #9818 / part2

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)

[DaveCTurner]

@prwhelan while you're working on the fix would you mute this in 8.x too?

[prwhelan]

@prwhelan while you're working on the fix would you mute this in 8.x too?

I pushed the fix to 8.x - I'll keep an eye on it over the next few days and mute if needed