For those wondering if it was intentional, this could have been done so that various PACs and other entities could "stumble" upon it and use the information in various capacities without fearing "coordination". I'm still skeptical that the party outright would have wanted this to happen.
Note that it happened the day before the June 20 elections
The article says that the investigation was done between June 1 & June 14, with the data being found on the 12th. Who knows how long it was actually there. It wouldn't necessarily make sense for the data to be placed there after the election (except for purposes like the one mentioned above), so it may very well have been there for the better part of a year.