@sam_s0ni  Apache NiFi never intended with the context of the NiFi framework to allow parameters to be dynamically accessed within NiFi Expression Language (NEL).  The EvaluateElString() exposed a bug in which this was possible while never intended.  That bug was addressed in apache NiFi 1.19 thus resulting in what you are seeing.   As an alternative, you could store your schemas in an external database and pull those schemas back dynamically based on a FlowFile attribute instead of using Parameter contexts to store those schemas. If you found that the provided solution(s) assisted you with your query, please take a moment to login and click Accept as Solution below each response that helped. Thank you, Matt ... View more

@sam_s0ni  Verify that all 3 NiFi nodes are: Running the exact same version of NiFI. Running the exact same version of Java 8 or 11 (only supported by newest releases) Contents of the NiFi lib directory, extensions directory, and any custom lib directories contain exact same content. Try removing the NiFi work directory from all three nodes.  On restart NiFi will rebuild the contents of the work directory from above lib and extensions folders. If you found this response assisted with your query, please take a moment to login and click on "Accept as Solution" below this post. Thank you, Matt ... View more