Had water coming on counter from anti siphon value.

My husband replaced it with a new one and checked the lines. The anti siphon value It is not connected to our garbage disposal, it goes into drain pipe. Kitchen has 2 sinks. The sink on the left had dish soap and water, and o when it drained detergent bubbles started coming on the anti siphon value on the right hand side of the sink, where the garbage disposal is and dishwasher. Ran the dishwasher and there was not any water coming out of the anti siphon from the dishwasher. Only when water and detergent are in the sink on the left. I did not try hand washing dist detergent. In the sink with the garbage disposal.

Why do bubbles come out of the anti siphon valve?