Why does my rice cooker's steam hole always clog?
If the foam from your rice cooker is reaching all the way to the lid, it may be over-filled. At least for very small grains, like quinoa, you may need to prepare it in smaller batches so that it can't be carried up to the lid.

Quinoa also has a coating of saponins on the outside of the grain. These soap-like chemicals can cause water to foam and also impart a soapy taste, they should always be washed off before cooking.

In general, adding a few drops of oil to the surface of the cooking water can help to reduce the amount of foam produced.