The cause of the issue has been identified to be, the way in which tcpdump configuration is captured. It does not have any limit on the number of files. Therefore, no file rotation happens and the number of files grows.
If the tcpdump is on, and number of packets passing through PCS box is large, the tcpdump command writes its output to a file tcpdump.dump and, if the file size reaches to 512 MB, continues to write multiple tcpdump.dump files. This will utilize the existing disk space of the device in data partition. Hence, as a result, the above SNMP trap messages is generated in the event logs.