Unfinalize line to cancel on PO is resulting in budget error ref'd doc has been finalized

PS FSCM PUM 47, PT 8.59

I have a client who attempted to unfinalize a line on the PO to resource to a different PO. Steps followed:

Go to PO schedule, line to be unfinalized

Unfinalize line

Budget check

Save PO

Cancel line

Budget Check — get error that Ref'd doc has been finalized

Requisition will allow line to be sourced to a new PO — neither PO will budget check successfully.

Any ideas?

Kari