We have not tested with this particuar tablet yet. But the problem is not with the android version 5.0.1, as we have already tested with this OS on different devices. Please confirm if this works on different devices with android 5.0.1
I'm afraid these are the only two physical Android devices I have available at present. Emulator of course will not work as it has no Bluetooth hardware.
I found I could set Security Level: "Unauthenticated pairing with encryption", I/O Capabilities: "No Input No Output", Bonding Requirement: "Bonding" and it works OK, both in CySmart and also in the Xamarin App I wrote for this project. So it seems it is just authentication or the passkey entry that is the problem on the Lenovo, not the encryption. This may suffice for my requirements as I can prevent the BLE chip bonding with more than one device and require physical access to delete an existing bond before it can be re-bonded to a different tablet.