it's not unusual for a little bit of dye to be released each time, upon time, and yes , the colour will fade a little.
It's often more noticeable with "delicates" as the dyeing and mordant process can't be washed clean as forrcibly as with other stronger fabrics.
I've had woollen jumpers that I wash by hand for years and there is a small ammount of colour released, but I'm not really aware of a huge colour difference, I just make sure that I've no whites in the bowl at the same time!