Why is steam releasing during pressure cooking?

There are a few reasons why steam may release during pressure cooking, so it's important to know where the steam is coming from. 

Steam releasing from the valve or the pin while the pot is coming to pressure is completely normal and it should stop when the pin pops up and pressure cooking starts. 

If you have steam coming out from around the lid, it's most likely a sealing ring issue and you will need to turn the Ninja Foodi off, remove the lid when the pin drops and check the sealing ring to make sure it is placed correctly. 

If you have steam releasing from the valve continuously during pressure cooking, then you may have a faulty lid or you have too much liquid in the pot. 

If the steam releases occasionally during pressure cooking and only from the valve, that is a safety mechanism and is normal. The valve is weighted and when too much pressure is built in the pot, it releases excess steam to reduce the pressure in the pot.