Many times, usually around month-end, I will get a call from a client that has a mis-match between their sub-ledger balance & their General Ledger. The first thing I will ask them is whether or not all batches in their Financial Series Post are posted. You can see from the screenshot below that GP will automatically create a number of batches in the Financial module after transactions have been posted in the Sales or Purchasing modules. Company configurations can vary, however, in general, a transaction posted individually in a subsidiary ledger will have to also be verified & posted in the Financial Series Post before it will affect the GL. Most transactions that are saved in the Financial Series Post have already affect the appropriate sub-ledger but NOT the General Ledger.
I advise clients to clear out all entries in the Financial Series Post daily to ensure accurate reporting and to be able to deal with any issues as they arise.