Is the tag map type not supported?

[JaeGeunBang]

I used the tag in the form of a map, but the following warn occurred. We have a config:

<source>
  @type beats
  tag ${record['level']}
</source>

/var/log/td-agent/td-agent.log

2020-09-17 15:34:24 +0900 [warn]: #0 no patterns matched tag="${record['level']}"
2020-09-17 15:34:24 +0900 [warn]: #0 no patterns matched tag="${record['level']}"
2020-09-17 15:34:24 +0900 [warn]: #0 no patterns matched tag="${record['level']}"

Is the tag map type currently not supported? Or is there a way to use tag as a map type?