I've noticed that my air intake temp sensor gives the correct ambient temp reading in the morning when the engine is cold, but that it typically is giving me readings between 7 to 17 degrees Celsius above the ambient temperature. Is that normal and does it have any significant negative effect?
Most of the time, intake air temperature is not the same as ambient air temperature.
This is because the air absorbs heat from the hot engine bay area before the intake air temperature sensor (IATS) measures its temperature.The heat-soak effect typically worsens on hot days and when the engine is under high loads.
Another factor to consider is that the IATS itself may suffer from heat soak, resulting in higher than expected readings.
Your observation in the morning also correlates with this; with the engine cold and no road heat (car parked overnight), it makes sense that the ambient air and the intake air temperatures match.
7-17 °C seems quite normal... one of my cars is notoriously bad - on really hot days the temperature difference can be as much as 40 °C!