Hi Affan,
When the event message processed, it would check EH exists when you sent along with EH. The event message may have sequence problem like event message comes before Event Handler created.
Can you check in the table /SAPTRX/EVM_UNPR those 20 event messages were sitting here?
Sequence when event message arrives to SAP EM:
1. Store event message /SAPTRX/EVM_HDR table
2. Check tracking id exist for EH ID, if unsuccessful
3. Then create an entry in /SAPTRX/EVM_UNPR
Once Event handler created, unprocessed event messages automatically assigns to relevant event handlers.
Regards
GGOPII