Different transactions, different POS names, but they are treated the same in Mint

I shop at Costco. My purchases from Costco show up as "Costco Whse". Gasoline purchased from Costco shows up as "Costco Gas". Very simple. Mint, however, shows them both as "Costco" and so any rules that I apply about changing the category apply to both.

I tried renaming one to "Costco Gas" manually and then changing the category to Fuel. That worked until I logged out. The next time I logged in, all of the Costco transactions showed up as "Costco Gas" and they were all categorized as Fuel. Why is it so difficult for Mint to differentiate between these? Why does it mess with things I've done manually? Renaming one transaction shouldn't rename any others if I do not check the box on the rename screen. They are totally different kinds of purchases, so lumping them together effectively kills the purpose of using Mint to analyze expenses at all.