I had this issue yesterday when I purchased the Chicago landmarks.
What I noticed was that the download would start off at ~12Mbps, continue for a while and then drop down to ~1Mbps suddenly and after that it’s very flaky. Most of the time the download would just stop and say Failed. Couple of times it got itself back up to 12 and continue. After about 5 attempts, it was able to install completely.
Network on my side is definitely not an issue, I have a gigabit connection.