Logical system &1 must be mapped to Logical System &2 in BDLS UI

What causes this issue?

In the Prepare task list SAP_BW_COPY_INITIAL_PREPARE run in Original BW
system, you have entered &V2& as the Target Logical System.
But in the parameters of Initial Copy Task list
SAP_BW_BASIS_COPY_INITIAL_CONFIG, BDLS UI contains wrong mapping for
Original Logical System. This will lead to erroneous delta loads in
target system.

Error message extract from SAP system. Copyright SAP SE.