A rinse cycle is required after dying to remove excess dye. Sometimes not enuf time or volume of water can cause residual dye to remain. Usually goes with first use however red and black are particularly difficult to rinse out.

Another problem may be that not enough "fixer" was used in the dying process that can result in a wash-out. This is more of a problem because your lmaterial will lose it's intended color and usually fade.

The net result in either case is anything nearby is subject to getting colored by the excess dye. Unfortunately there is no way to tell in advance if this is a problem so the best you can do is keep like-colored things together.

hope this helps.