Hello,

On a General Journal Batch, you can check the field Suggest Balancing Amount.
When this feature is enabled, the Document No. is no more auto-incremented when the balance reaches zero.

You can reproduce this behaviour by following theses steps:
1. Go to a General Journal
2. Open the General Journal Batch and check Suggest Balancing Amount
3. Type a first line with an Amount = 1,000
4. Type a second line, it will be filled with Amount = -1,000 automatically
5. Start a third line, the Document No. is still the same as before.

I think the expected behaviour would be to increment the Document No.