For each bulk there is a fuse to limit the number of merges in the bulk. The reason is due to more memory being used and the bulk takes longer.
Also, this error can be a warning in order to check the topology that should be merged.
The fuse to be increased is reconciliation.merge.operations.fuse The new value can be set to 3000 as per the below steps:
1. Open UCMDB JMX Console
2. Find UCMDB:service=SettingsServices>setSettingValue section
3. Enter CustomerID: 1
4. Restart UCMDB services
5. Then, run the Population job