Problem
The Bill To information on an invoice does not update to match the Bill To information on the job record.
Solution
Search for and go to the invoice in question.
Check if the Bill To information on the job record is correct. If not, update it there first.
Return to the invoice.
Change the Bill To information back to the original one.
Now, change it again to the correct Bill To information.
Verify that the Bill To information on the invoice has updated to match the job page.