Multiple Messages with same id in moni

All

I have recently observed that for the interfaces involving BPM, I can see two entries in SXMB_MONI. Everything is same in the two entries except the value of Pipeline, i.e. CENTRAL and PE_ADAPTER.

This case is only for those scenarios where we have sender side as IDoc.

IDOC-> BPM->WEbservice

But in rest of the cases (File -> BPM -> File // Soap->BPM->RFC) we can see only a single entry in Moni but inside we can see multiple messages inside as shown below

What is the reason for this?

Madhav