Very strange that, throughout the report, it is noted that there are "no comprehensive federal regulations specifically targeting dietary exposure to heavy metals" and yet in all their results they present violations as exceeding "federal or state" regulations. What federal regulations are they evaluating if there are none?
Looks like Prop65 lead limits are 20x lower than conventional USP limits, so even exceeding 2x Prop65 puts you 10x below USP limits [1] for daily exposure. A serving of protein powder is ~10% or more of daily caloric needs so this seems perfectly reasonable.