I purchased a new package of yeast. It's a about a 2x2x3 inch vacuum packed brick of granulated yeast for baking. I've purchased and used it twice before without a problem. It's always had normal taste and smell in the finished bread or rolls. This time the rising rolls had a strange odor and similar taste. The process takes 15 minute kneading, 1 hour rise, 1 hour roll rise, 14 min bake. The only Variables are the dry regular rise yeast and the 1/2 cup of whole milk. The granulated yeast is stored in airtight jars in refrigerator. The milk had a very small amount of cream on top. Rise and bake was perfect. Why the smell and taste problem? The yeast is a product of Mexico.
You could try testing the yeast in isolation by blooming or proofing it.
Take half a cup of warm, not hot, water (about 100°F), dissolve a teaspoon of sugar in it, sprinkle in a good spoonful of yeast, stir, and then wait for it to bubble. Should take about ten minutes. If you get the weird smell again, you've found the problem; if you get a normal yeasty smell, the problem was probably a different ingredient. (If it doesn't bubble at all, either your yeast died of old age or you made the water too cold or hot.)
I highly doubt that the yeast is the source of your problem here, if you used it twice before without issues it's probably still fine. Most likely the smell has been caused by bacterial growth from another source, likely the milk, which is a good medium for bacteria. If your milk was close to going off it may have already had some off flavors in it, and if it was already starting to have significant bacterial growth that would have accelerated when it was rising/proofing.
I would suggest using fresh milk, or heating the milk to 72°C/165°F to kill the bacteria before using it. You'll need to cool it down before you use it, so plan accordingly.