Github user markap14 commented on the issue:
https://github.com/apache/nifi/pull/2207
@frett27 @mattyb149 I think what is done in this PR is actually correct
as-is. The issue you're running into, @mattyb149, I think is that the Avro
Reader is returning a MapRecord object when it should in fact return a Map
object (Any time a RecordFieldType is MAP, it should return a java.util.Map for
the value). So I will address that as part of NIFI-4767. +1 merged to master.---
