No, what it does is ocassionally allocate the same invoice number as the previous invoice. Eg, I raise an invoice, it allocates, say, 18125, I send it and then go to raise a different invoice for another customer, fill it all in, press send, go back to my list of invoices only to see that the second invoice is also numbered 18125!
Ah I see. First we need to try some troubleshooting steps. Could you please clear your cache and cookies? You may need to search how to do this for your browser if you are not sure. Make sure to select All time if it asks for a time range. Once you have done this, refresh QuickBooks, log back in and then try to create new invoices to see if it is numbering them correctly.
Let us know how you get on.