While trying end date relationships giving error: ORA-01436: CONNECT BY loop in user data

 Dear experts,

We are trying to end date relationship through Contact centre form and getting the error:ORA-01436: CONNECT BY loop in user data.

The original problem started when doing Party Merge. Party merge errored with the below error:

"The following parties cannot be merged because they belong to separate hierarchies. Please remove the hierarchy relationship for one or more of the parties or have your administrator allow parties to participate in multiple hierarchies.

Parties: 241062, 245911

.... One or more of the Merges in the batch had errors"

When we tried to end date the relationship where it got errored ORA-01436: CONNECT BY loop in user data  error is coming.