[CI] StatementParserTests testNamedFunctionArgumentInMap failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #6088 / release-tests
• elasticsearch-periodic #6083 / release-tests
• elasticsearch-periodic #6076 / release-tests
• elasticsearch-periodic #6071 / release-tests
• elasticsearch-periodic #6066 / release-tests
• elasticsearch-periodic #6061 / release-tests
• elasticsearch-periodic #6056 / release-tests

Reproduction Line:

./gradlew ":x-pack:plugin:esql:test" --tests "org.elasticsearch.xpack.esql.parser.StatementParserTests.testNamedFunctionArgumentInMap" -Dtests.seed=818EC091DBFFCEAF -Dbuild.snapshot=false -Dtests.jvm.argline="-Dbuild.snapshot=false" -Dlicense.key=x-pack/license-tools/src/test/resources/public.key -Dtests.locale=frr-DE -Dtests.timezone=Europe/Guernsey -Druntime.java=23

Applicable branches:
8.x

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

org.elasticsearch.xpack.esql.parser.ParsingException: line 2:12: no viable alternative at input '?fn1'

Issue Reasons:

• [8.x] 7 consecutive failures in step release-tests
• [8.x] 7 failures in test testNamedFunctionArgumentInMap (1.7% fail rate in 413 executions)
• [8.x] 7 failures in step release-tests (100.0% fail rate in 7 executions)
• [8.x] 7 failures in pipeline elasticsearch-periodic (100.0% fail rate in 7 executions)

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

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[alex-spies]

@fang-xing-esql , is this maybe related to your work?

[alex-spies]

Duplicate of #121020, @ChrisHegarty was faster than the bot, ha.

[fang-xing-esql]

Thanks for the ping @alex-spies @ChrisHegarty, I'm looking into it.