When entering Invoices in a FAST batch, GST Sales Tax may be set to 0% in the database configuration. When this is the case $0 defaults for the GST tax amount. When this is initially entered, the $0 defaults correctly, but after the batch is saved, the $0 is wiped away and a validation error results when attempting to commit the Invoices.
We are currently evaluating this issue and will update this article when we have more information.
Currently, it's still possible to commit successfully prior to saving the FAST batch.
Steps to Duplicate
1. Create a new FAST batch 2. On the design tab, scroll down to the separate GST Sales Tax section, and add the "GST Sales Tax" field that includes Tax Entity ID, Amount and Percent 3. Select the Datasheet tab 4. Add in info for all fields using some sample information using a Vendor that has a default distribution that includes GST 5. Notice that the GST Amount column shows as $0 6. Save and close the batch and reopen it 7. Notice the $0s are no longer there 8. Attempt to commit the invoice > receive validation error - GST Sales Tax 'Amount' is required