Anonymous
this is known as stacking in the valve. cauesd by poor casting when the valve was made. Ive had numerous higher end brands as well as cheapies do this. there is actually a void in the casting which doesnt allow the valve or seal to do their job. fairly certain these parts are in top shape as its most likely a new install. hate to say it but take it back to where you bought it and try diff brand unless youre just in love with this particular style, or cross your fingers if you replace with same model