Your web application interacts with a DynamoDB table, performing both read and write operations. The table in question is configured with a total of 400 Write Capacity Units (WCU), distributed evenly across 4 partitions. This means that each partition can ideally handle up to 100 WCU. However, one of these partitions is receiving 250 WCU per second, substantially more than the other partitions. Consequently, you encounter the error message 'ProvisionedThroughputExceededException'.

What is the most probable reason for encountering this error?