In summary: lead to wrong financial figures
In detail: The behavior causes the sales tax to be calculated on top of the sales line amounts, which leads to a discrepancy between the transaction total and received payment as generated by the AX7 Cloud POS on the one hand and the sales order invoice generated in the AX7 backend on the other hand
Current behavior was looking up for Return line's original line to get original PRICESINCLUDESALESTAX value. The issue was that if original sales line was not found, the code didn't check for it and still tried to obtain PRICESINCLUDESALESTAX value. In this case, PRICESINCLUDESALESTAX always falls back to FALSE.
The fix is to check if original sales line was found and then only obtain PRICESINCLUDESALESTAX value. Otherwise PRICESINCLUDESALESTAX value comes from channel configuration.