Unreliable nearable discovery in Android

While using onNearablesDiscovered() on an Android project, I can see that almost half of the times this is run (~45% in a 5 mins. test run of my app) the device cannot identify a Sticker that is sitting right next to it. The longest period of inactivity is almost one minute, while the average inactivity period is about 10-15 seconds. After these periods, it identifies the sticker again.

I’m using a Nexus 4 and can confirm that the Estimote app is also buggy on this device (i.e. sometimes it cannot find nor connect to stickers), so do you think this is a hardware problem?
As a side note, I’ve also developed an iOS app which listens for region changes and trigger monitoring and don’t seem to run into these problems with the same sticker (using an iPhone 4S).

Do you have any suggestions to improve performance on Android?

PS: Tried contacting support via email with the same issue since last week, but got no response at all.

Update: I can confirm that this not only applies to stickers (nearables), since I made one of my other stickers send iBeacon packets and used startMonitoring() and setMonitoringListener() as if I was using a regular Beacon, and I can see that the device exits and enters the region constantly, which also appears to indicate that the device looses connection with the sticker, even when sending iBeacon packets.