Android App - Says synchronised with 3+ devices

I'm struggling with the Android application. It's just told me that I have synchronised with more than three devices and so it will desynchronise itself. I've been logged into my account on three devices (2 PCs & the phone), but not simultaneously and I have only downloaded playlists for offline listening on the Android device. I've changed the security settings on my account so I don't think a third party is logging in without my knowledge.

Has anyone else experienced problems with the Android app (particularly re: synchronising playlists for offline listening)?

At the moment the service I'm getting from the app is patchy at best.