The ISQ number for new owner & system will be re-assigned if invalid.

What causes this issue?

You have specified an ISQ number for the new owner. When the background
process runs, it will check the next number in sequence for the owner's
ISQ. If the number you have specified is not the next number in
sequence, it will re-assign the correct number and overwrite the number
you specified.

System Response

This is an information message only. No action needs to be taken.

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.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.