There’s a lot of internet scary stuff circulating around. I don’t give it a second thought. Fact is at many pumps you do not know because the label says “may” contain up to 20% etc. And diesel is a commodity where the buyer or wholesaler will substitute depending on price and availability.
We were dealing with water in fuel and biological growth in diesel decades ago. These are not new problems.
What HAS changed is the removal of sulfur and the increased operating pressures in injection systems. But that’s a different can of worms entirely.