Issue 1:
The "10270010000404" receipt was assigned to the "27-27001-1373" cart. But checkout failed and cashier suspended the cart. When cashier resumed the cart a new receipt id was generated for this cart. That is why we see the gap in receipt ids. It's by design.
Issue 2:
transaction number for a voided item.
“this is a known limitation with our receipt number sequence generation and what they're seeing is by design. Receipt number is advanced after voiding previous transaction. Exactly what your colleague did to reproduce the issue is why this happens for our customers.
This was not caused by any system upgrade and has been like this since forever. In the future in 10.0.38 we will remove the receipt id from the voided transactions as you saw through an existing work ticket we have in place for this enhancement. When Checkout API failed then the cart was voided or suspended, the receipt number is still captured on the retail transaction.”
this is by design.