Mobile phone devices are combinations of different hardware and software. Powerpal device hardware and software is compatible to communicate with all major mobile handset devices. Due to different sets of software and communication protocol used by manufacturing companies, some users get constant paring requests.
Powerpal devise uses Bluetooth Low Energy v4.2, which is a completely different protocol to standard Bluetooth as used by other devices such as headsets - the only relation is the Bluetooth name, technologically they are completely unrelated.
The bug some users are experiencing is a well-known issue with older versions of Android and is related to a bug in the specific version of the Bluetooth LE v4.2 communications stack which was licensed by certain manufacturers (Such as Nokia and Oppo). Unfortunately, the only way to fix this issue is to upgrade to the version of the stack where this bug is fixed, which requires an upgrade of the Android OS.
If you cant upgrade your Android OS then, the only way to resolve the issue is to connect Powerpal with another device or upgrade your device.