Elasticsearch Version

8.15.3

Installed Plugins

No response

Java Version

bundled

OS Version

debian

Problem Description

While using ESQL, the following issues were encountered:

1. Issue with ENRICH and != Binary Operator
   The search stops functioning entirely when combining the ENRICH command with the binary inequality operator (!=).

Example Query:
FROM logs-system.* METADATA _id, _version, _index
| WHERE event.category == "iam" AND winlog.api == "wineventlog" AND event.action == "added-member-to-group"
| ENRICH policy_role_idm ON user.name WITH user.role_name, user.role_type
| WHERE user.role_type != "Multirole"

The above query fails to return results or crashes unexpectedly.

2. Partial Issues with Cyrillic Values in Filters
   Filters using Cyrillic values in WHERE clauses show inconsistent behavior.

Example Queries:

Fails:
| WHERE user.role_name == "Адміністратор WIndows"

Works:
| WHERE user.role_name == "Локальный администратор на ПК"

Expected Behavior
The != operator should work seamlessly with ENRICH.
Filters with Cyrillic (Ukrainian) characters should behave consistently and return expected results.
Actual Behavior
The != operator fails in combination with ENRICH, causing the query to stop functioning.
Filters with specific Cyrillic strings (e.g., Ukrainian characters) do not return expected results.

Steps to Reproduce

1. Run the provided ESQL queries.
2. Observe the inconsistent behavior with != and Cyrillic values.

Logs (if relevant)

No response