I expected the Swap Handling Fees to be incurred at a positive value but they incurred at a negative (minus) value.

The Swap handling fees are assigned based on VWAP. VWAP is based the weighted average of the total sales volume that occurred in the previous hour.

As a result, the value assigned should not be used as a reference.

Please refer to the AirFX Swap Handling Fees Calculation Method for more information.