End-date of the new assignment has been re-set

What causes this issue?

The system has found an assignment record which begins during the
interval of the new assignment. As overlapping assignment records are
not allowed, the end-date of the new record has been set to match
the start-from date of the earliest assignment record beginning during
the specified interval.

System Response

The system proceeds.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.