I think we are having two different problems here: one in which Spotify is using data while the playlist is saved online (which already was functioning this way for years) and mine problem in which Spotify is just using way to much data for one song. (No offline modes)
I'm having the same issue. Up until a week ago my data usage was moderate (would usually hit my cap towards the end of the month). I use Spotify whenever I'm on public transport, but I have playlists saved and never stream songs.
All of a sudden, in the last week, I've used an extra 4-5GB of data just by playing music that has already been downloaded to my phone!
Based on the above two options:
1) Spotify is still streaming music for some reason, despite having it saved to my device which totally negates the point of having music saved to your phone; or
2) There's a bug which is causing data to be excessively used.
Either way, I've been charged over $40AU by my carrier just for trying to listen to music like I used to. Spotify better have some answers, and fast.
I suggest we all contact Spotify support, linking to this thread, asking for a definitive answer on whether this is indeed a bug, or by design with the latest version. I was told by a support guy it was by design, but I really think he just didn't know what he was talking about. The more people that contact them regarding this issue, the faster will get a fix, or at least an answer. And if it is by design, then Spotify needs to start informing all of its users ASAP.
Their line about it being by design is just crazy. I decided to remove Spotify till this is fixed. But I was going insane at work with no music. I ended up taking up my ISP on its one year free Apple Music offer to fill the gap.
After dealing with Spotify destroying my cellular data I initially thought Apple Music was broken, or hiding its data usage somehow. It seemed so low. Then I realised Spotify used to use the similar amounts before the early April update. I still prefer Spotify, so I hope they fix it soon.
Talking to support can be a bit like banging your head against a brick wall. But you just have to stick it out while they work through their script. It's kind of frustrating that the person replying to my emails would change frequently. I was often asked for details I had mentioned in previous emails. I mentioned this thread and others like it each time as well.
I normally do not use offline playlists, but when I did it used data. It already does that since years ago, there's nothing really new on Spotify using data on playlists that are saved offline. I don't get what the problem is.. Just turn Spotify in offline mode and it's fixed.
I think my problem in which Spotifys uses about 2GB a hour is much more concerning.
I understand that it would use some data in order to update play counts, album art etc. But why bother streaming a playlist that I already have in higher quality saved to my phone?
This was not an issue a month ago. Something definitely has changed, either by error or on purpose, neither of which is acceptable. I shouldn't have to toggle Offline mode on and off every time I leave a wifi area, just like I didnt have to a month ago.
I've used offline playlists for over a year, (I only signed up for Spotify last Jan).
I've never put spotify into offline mode. It's pretty much used no data in the past beyond a pittance which I assumed was adminy stuff, misc lookups, scobbling etc. The only restriction I've ever put on Spotify was making sure the 'download over cellular' was off.
Up till this year I had a small cap of under 2GB. I would sync my playlists in the morning on WiFi and head out the door. I never put spotify into offline mode. I rarely went over a couple of hundred mbs in total for everything, (not just spotify), I used online.
It was only this year that I got a decent data plan and started streaming more. But out of habit I still synced my regular playlists. But I started streaming from the other spotify playlists about 1/2 the time when I was out. Last month I used about 1 1/2 GB in total, not all of it Spotify. The first few days of this month, with no change to my habits, Spotify used more than that on its own.
Now I'm getting massive data usage for everything spotify related, be it online streamed or downloaded files. I suspect it's linked because it all started after the early April update.
That is weird. Im 100% sure that when I used a Spotify offline list 2/3 years ago it simply was streaming it anyway. Maybe it changed afterwards and now they changed it back? I also do'nt get the point of a offline mode when you wont use data if they're already downloaded. Maybe it isn't possible on iDevices by Apple developer restrictions.
I don't know what to say, man. Up till this month, downloaded files/playlists worked the way I assumed they would work when I joined up. That is, if a track was downloaded, it wouldn't use your cellular data to stream it again.
I used MOG before I had spotify. And downloaded playlists worked exactly the same way. It also had an offline mode that I never used. And back then I only had a 1GB cap and still never used more than a couple of hundred mb a month. Because cellular data was freaking expensive and I was too scared to use anything but downloaded playlists to avoid overuse charges. Still never set it to offline mode though.
With Spotify, I stream at normal, but download at extreme. If I'm playing back a downloaded playlist when I'm out and about, I don't want to stream it at lower quality when it's already sitting on the phone in extreme quality. It's one of the reasons I still download my favourite playlists. For the better quality. Whether or not I can really tell the difference when I'm out and about is still up for debate though.