Debugging API Key authentications

Hello,

I have a 3 node Elastic cluster. Everthing is working fine, but I wen't to the Logs to debugg something else that I ended up fixing and I noticed these warnings:

{"type": "server", "timestamp": "2024-03-22T16:33:56,992Z", "level": "WARN", "component": "o.e.x.s.a.ApiKeyAuthenticator", "cluster.name": "elk-cluster", "node.name": "node-2", "message": "Authentication using apikey failed - api key has been invalidated", "cluster.uuid": "mceikJOASzQpX9sYrskcbg", "node.id": "zLzmDns4SaqPTfrQ0UK6NQ"  }

All the errors come from node-2. How can I debug this further to find out what is using API Keys? As far as I'm aware, all my scripts/tools authenticate to Elasticsearch on all nodes (all tools have an array of nodes) and all use username and password. Does this ever happened to anyone? I tried looking for other log files, but so far nothing came up.

Cheers