Courtesy of the Internet Archive's Wayback Machine, here's an image from DEWM's website in early 2012 that shows that the purple LEAN has been called "Purp" since at least 2012, and that the labeling appears to be the same as the can on the MildWildCo site:
Finally, I grabbed the image itself, then copied the image of the "Purp" can from the MildWildCo site, and added it to the DEWM image from 2012. The cans appear identical:
It's very likely that MildWildCo is selling very old, outdated stock of LEAN.