Content Transfer between WSUS and SCCM client on port 8530

Dear All

In my environment from last few days we are facing an strange situtaion where huge contents is getting transferred between WSUS server and SCCM client on port 8530.

I check logs on client and found that client are getting contents from their associated DP's but still weekly network utlisation report showing that data in GB's was transferred between SCCM primary server and clients on port 8530.

Kindly suggest what else need to check in this scenario

Regards Suresh