_grokparsefailure with kv

Hi, I am using

kv { }

filter but output in Kibana have tag _grokparsefailure, why? Output looks like is fine, without errors however still have this tag, when I even don't have grok (only input udp, filter kv and mutate for remove field and output to ES).

Sometimes also there is _jsonparsefailure, when there is no json in config and data source, why?

That suggests you are not running the configuration you think you are. Try adding--log.level debug --config.debug to the command line and see what configuration it is loading.