I just did.
You're looking at it wrong. It doesn't matter if the second crime uncovered looks similar enough to the first crime. What matters is whether or not they found evidence of the second crime while within the scope of the first.
Now I'm sure you'd agree that part of investigating about coordination with Russians would include a look at finances. So if they found evidence of a second crime while looking at said finances, it's within the scope. Doesn't matter if that second crime is drug smuggling, paying for donkey shows to be hosted on a yacht, or anything else. So long as it was uncovered through financial records, they're good. And given that one of the accusations for the trump team is that they were making deals with foreign nationals before actually in office, I'm not sure how you can argue that a deal with a different foreign entity (which would likely be found through similar financial disclosures) wouldn't be something they could possible come across during their initial investigation.