Shufflizer download
When Shufflizer says it is downloading it means just the track listing, not the songs themselves:
Shufflizer upload
In Shufflizer, when you are done editing a playlist, you upload it. This commits your edits to Spotify:
There is a date added for each song in a Spotify playlist. Because Shufflizer upload is redefining the playlist, all of these dates change to the current date. Here is an example showing the dates in the Spotify desktop app, right after an upload from Shufflizer:
Spotify download
Spotify also has a download. It means something different. In Spotify, download means downloading the songs themselves, so you can then play them without incurring data charges or when you don’t have an Internet connection.
Shufflizer doesn’t know about and is not in any way affected by Spotify download.
