I haven't had that issue, but a few questions might help isolate what's going on:
1. In the screenshot there appears to be music playing - does this only happen when you have music playing? (Was it streaming or local content?)
2. Looks like you're using PIN mode to unlock - have you tried a different security method, or tried turning security off altogether to see if that's causing the problem?
3. How often does it occur - one in ten times, five in ten times?
4. Are you using an alternate launcher?
5. Stock? Rooted? Unlocked? etc...
EDIT: There are a couple of icons I don't recognize in the notification bar (one might be Lookout or a similar security app) - have you tried disabling those apps to see what happens?
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