Hello Padma, this looks similar to the known threshold issue with partitioned Identity Refresh tasks. The same behavior was reproduced on IIQ 8.4p2, where lifecycle events fired even though the configured threshold was exceeded. There is a SailPoint support case for it (CS0389766 / IIQETN-12661). You can see the details in this thread, post #8 specifically.
Please test the same refresh with partitioning disabled and make sure no aggregation is running in parallel. If the threshold blocks the events correctly, it strongly points to the same issue. Disabling partitioning can be used as a temporary workaround, although the refresh may take longer.
Since you are on 8.4p3, I would raise a support case and reference CS0389766 / IIQETN-12661 to check whether this was fixed for your patch level. Until that is confirmed, I would not rely on the threshold alone while partitioning is enabled.