Setting tag in eval not persisted in alerts

For example tag value is not persisted.
|eval(lambda: string("last_value"))
.as('value')
.keep('value')
.tags('value')
|alert()
.crit(lambda: "value" <= 0)

Now the alert data should have a tag for value along with all the group by. But apparently that is not the case.

Reproduce the issue with the eval, keep, tags, and alert pipeline shown in the report. Trace how the alert data is assembled and verify that the value tag is retained alongside the group-by tags when the behavior is fixed.

Written by the indexing model from the issue text.