Cardex document number for sales orders does not equal invoice document number in F42119 or F0911

Hoping someone can answer this, as I have not been able to find an answer in Oracle Support search. For some of our sales orders that ARE NOT interbranch or intercompany, the document number in the Cardex transaction is not equal to the invoice document number. Orders are written to Cardex at ship confirm P4205 and not through sales update R42800. I can only find in documentation that Cardex number would be different for interbranch type orders. It appears the numbering is using the same string of next numbering as RT documents get, but are an