Hi KDEES
Welcome to the Community Forum. The automatic invoice numbers tries to be helpful and fill in the gaps, so this can happen when a invoice is deleted or when converting quotes to invoices, it will use a blank spot not currently being used. The problem occurs when it does that and the next one will be that number +1. (which possibly is already used)
The best way to fix this is to pick a higher number and type that in a few times (e.g. if its doing 101 you put in 201, then 202, 203 etc. until it picks up the new pattern and auto-fills correctly).
To avoid the issue you have with those 4 invoices using the same invoice number as other invoices, I recommend turning on the preference "Warn for duplicate invoice numbers on recorded sales". This can be found under the Setup then Preferences window, then under the Sales tab.
if you have any further questions, please let me know.
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