Dynamics GP - After applying a payment to an invoice, the amount remaining is incorrect

Problem:
Amount remaining on an invoice is incorrect

Cause:
Sometimes, if something goes wrong during payment application, the transaction can get locked or stuck. The amount applied may be updated, but the transaction may not be truly applied.
When the transaction is unstuck, and the payment redone and reapplied, it causes the amount remaining to deduct a second time, resulting in an incorrect amount remaining.

Solution:

• Unapply all applications to the offending transaction
• Check the application tables to confirm no other records
• select ortrxamt, curtrxam, * from rm20101 where DOCNUMBR = 'myinv            ' (check the curtrxamt on the transaction)
• select * from rm20201 WHERE APTODCNM = 'myinv            ' (confirm nothing else applied)
• If there is nothing applied, then manually update the CURTRXAMT field in the RM20101 table
• Update RM20101 set curtrxamt = 'myamount' where docnumbr = 'myinvoice'
• If this is a multicurrency transaction, you also have to update the Multicurrency RM table MC020102
• select ORCTRXAM, ORORGTRX, * from mc020102 where DOCNUMBR = 'myinv'
• update mc020102 set ORCTRXAM = ORORGTRX where DOCNUMBR = 'myinv '