Listener Deduplication Syntax

I am using a listener to take in requestIds that start an automated process. When setting it up, there were some situations where the requestId was sent twice and I wanted to avoid the processing being called twice, so I added in Deduplication configuration in the listener. The request body being sent to Moveworks is always in this format:
{“requestId” : “<id>”}

Therefore for the deduplication, I added requestId as the Deduplication key (no spaces or quotes) with a 1 min window. However I am noticing that it is blocking requestIds that are not equal but are sent within the 1 minute timeframe. The difference between them in these cases is the last character in the requestId (ex ABC1234 vs ABC1235) In the logs, I am seeing one go through and “debounced_update” log entries for the other requestIds sent. I have no event filtering enabled for the 1 plugin that is associated to this listener. Please assist me in understanding the root issue and how to set this up correctly as the “debounced_update” points to an issue with the Deduplication setup.