The logic for the cache in `JwtRealm` produces a broken `Cache` instance to some degree. 
We create a `BytesArray` from the user credential hash:

```java
            final BytesArray jwtCacheKey = isCacheEnabled() ? new BytesArray(jwtAuthenticationToken.getUserCredentialsHash()) : null;
            if (jwtCacheKey != null) {
                final User cachedUser = tryAuthenticateWithCache(tokenPrincipal, jwtCacheKey);
```

and use it as as a cache key in a `Cache` instance down the line.
But then we also clear the bytes in that `BytesArray` to `0` in org.elasticsearch.xpack.security.authc.jwt.JwtAuthenticationToken#clearCredentials. 

This leads to the hash map in the `Cache` getting filled with loads of `BytesArray` that all have the same 0-filled content but that were not equal to each other when first inserted into the map, causing the map to put them all in the same bucket.

<img width="1233" alt="image" src="https://github.com/elastic/elasticsearch/assets/6490959/86a914d7-a2d4-4b01-ad99-e0d14e71a58b">

ref path to the broken map:

<img width="1436" alt="image" src="https://github.com/elastic/elasticsearch/assets/6490959/87ac6f78-bc09-41c4-9a79-28fbbd14f6e6">

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/jwt/JwtRealm.java
+ claimParserPrincipal
                + "] claims=["
                + claimsSet
                + "].";
            logger.debug(msg);
            listener.onResponse(AuthenticationResult.unsuccessful(msg, null));
            return;
        }
        
        final ActionListener<AuthenticationResult<User>> logAndCacheListener = ActionListener.wrap(result -> {
            if (result.isAuthenticated()) {
                final User user = result.getValue();
                logger.trace(
                    () -> format("Realm [%s] roles resolved [%s] for principal=[%s].", name(), join(",", user.roles()), principal)
                );
                if (isCacheEnabled()) {
                    try (ReleasableLock ignored = jwtCacheHelper.acquireUpdateLock()) {
                        final long expWallClockMillis = claimsSet.getExpirationTime().getTime() + allowedClockSkew.getMillis();
                        jwtCache.put(jwtCacheKey, new ExpiringUser(result.getValue(), new Date(expWallClockMillis)));
                    }
                }
            }
            listener.onResponse(result);
        }, listener::onFailure);
        
        if (delegatedAuthorizationSupport.hasDelegation()) {
            delegatedAuthorizationSupport.resolve(principal, logAndCacheListener);
            return;
        }