Confirm that G1GC is still set as the garbage collector in your bootstrap.conf.
There really isn't much more to this reporting task.
How long did you leave it running? Do you have an active dataflow that is constantly using JVM memory?
By default this reporting task only runs every 5 minutes. So at the time it runs the threshold would need to be exceeded. Could it be possible that your memory usage is going up and down but overall is low enough to just not trigger? Try running a constant flow of data that is allowed to queue on some connections. Since FlowFile attributes live in memory up to the swap threshold, there would be a constant heap memory usage. See if that does not cause it to trigger.