Hello there, awade,
It's possible that the job you moved has no pending transactions. You can delete and recreate the payment associated on that job. Make sure to take note of the payment details before deleting it.
After that, try moving the job to the customer again. Once merging is done, you can recreate the payment.
Here's an article for more information: Merge Accounts, Customers, and Vendors.
Don’t hesitate to comment below if you got additional concerns, I’m always here to help you.