AprilBeacon-Android-SDK return 0 item sometime

I try to run demo from https://github.com/AprilBrother/AprilBeacon-Android-SDK.
When run AprilBeaconDemo app and it callback to onBeaconsDiscovered.

Sometime It’ll return correct item list.But sometime it’ll return 0 item.
I founded problem in Android 7.0.But in Android 5.0 it can work perfectly.

Any one found problem like this ?

Yes it have the problem.

Thanks so much for your answer.
Can I fix or workaround for this issue ?