We have a washing machine that is 2.5 years old. Today when washing a load of clothes, water came up in the bathroom sink while it was in spin cycle. This bathroom is right behind where the washer is. When the water drained out of the washing machine, it also drained out of the bathroom sink.

We had that problem last year but it came through our bathtub and toilet instead of our sink, our problem was roots in the lines, just a suggestion to look into

This has nothing to do with your washing machine. You have a partial blockage somewhere in your drainpipe. When your washing machine is on spin it is initially draining too much water to get past the partial blockage so the water backs up the pipe. Your bathroom sink must be attached to your laundry drain before the blockage so the excess water rises back up the bathroom pipe. When the flow of water from your washing machine slows down this lets the water in your bathroom sink drain back past the partial blockage.

Try using some drain cleaner (caustic soda) down the bathroom sink. This may dissolve the blockage otherwise you may need a plumber to clean out the drain.