Description
First of all this issue was already reported numerous times over last two years. Unfortunately it seems it never got proper attention (I would place there few links with examples, however this forum is rejecting my posts with links for some reason...).
It would be nice if someone from the moderators could finally file this as a bug. The problem is that play queue disappears after random period of time. You listen to music, then pause it (not terminating the app or anything like this, you simply pause the playback), lock your screen and couple of minutes (this can vary – it could be after one minute as well as after 20 mins) when you unlock your phone again, your play queue will be gone – your ‘now playing’ screen will be grey with play, forward and backward button (see attached screenshot)
 
What are the steps you took to get to the error/issue?
1.      Open Spotify on Android
2.      Select a random playlist or song
3.      Play it for a while and then pause it
4.      Do not terminate Spotify, simply lock your screen and wait for a while
5.      Then unlock your phone again and check if the play queue is still present
6.      If it’s gone, you’ll see a gray sceen (see screenshot)
 
What I expected to happen
I expect that the app will remember what’s in the play queue and the position where the last played track was stopped, so when I unlock the phone I can resume listening from the point where I stopped before (that’s how the desktop app works)
 
Did you restart your device when troubleshooting in section B?
Yes
 
Did you read the connection troubleshooting tips?
Yes
 
Your device
Motorola MotoG 4G
 
Device’s Operating System
4.4.3 KitKat
 
What type of account do you have?
Premium
 
(FYI for the below points: Android devices tend to refer to the internal memory as "SD Card" and the SD card you inserted yourself as "External SD Card")
Space left on your device
1.5 GB
 
Space left on your SD card (if applicable)
N/A
 
Space left on your External SD card (if applicable)
25 GB
 
Is your device rooted?
No
 
Are you using a custom ROM, if so which one, exactly?
No
 
Did you set your external SD card as storage location?
No – app is installed on the device and offline music is stored wherever you have the most free space available as far as I know
 
Did you manually install an older version before installing the latest version from the Play Store?
No
 
Do you have the same issue when switching between WiFi/Mobile Data (If applicable)?
Yes
 
If you said "No", when does the issue not occur?
N/A
 
My mobile Spotify version
1.3.0.423
 
My desktop Spotify version (if applicable)
N/A
 
My mobile provider and country
Vodafone CZ
 
My username
1218955311
 
Do you have a Spotify (non-Facebook) login?
Yes
 
Are you logging in with Facebook or with your Spotify login details?
Both – there’s no difference in relation to this bug.
 
Do you have any screenshots you can attach to more clearly explain your issue?
See attachments
 
Thank you!