Can't scan or connect to peripheral device without restarting Node-RED

[contrabass22]

Symptoms

1. Checking "BLE Scanning" in a global Generic-BLE configuration node finds no devices after a long period of waiting. Unchecking, waiting a moment, and re-checking "BLE Scanning" exhibits the same behavior.
2. Trying to connect to a peripheral device fails, and the nodes are in either the "error" or transition to the "missing" state.

Workaround
Restart the Node-RED server. Subsequent attempts to scan or connect may succeed.

Details
The following log occurred at the time of the failure:

[error] [GenericBLE:ERROR] Missing Bluetooth Object, Path:/org/bluez/hci0, Valid Paths:/org/bluez}, Error: Missing Bluetooth Object, Path:/org/bluez/hci0, Valid Paths:/org/bluez}
    at BluezBindings.init (/home/user/.node-red/node_modules/node-red-contrib-generic-ble/dist/noble/lib/bluez/noble/lib/bluez/bindings.js:182:19)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Note that this issue can be compounded with #40 where even after restarting Node-RED may require the workaround of unchecking and/or checking "BLE Scanning" in the global configuration node to fix the issue.

Steps to Reproduce
This is an intermittent issue. There don't seem to be any unusual aspects of a flow to get this to occur. I've seen it happen on flows with different devices. All of them have an inject node to connect to a peripheral device. The GATT characteristics they read/write don't seem to affect the behavior.

Component Versions
Platform: Linux armv7l (32-bit)
Bluez: 5.54
Node.js: v10.16.3
Node-red-contrib-generic-ble: 4.0.3
Node RED: v1.2.9

Hardware
Bluetooth adapter: TPLINK UB400
Peripheral Device: TI Sensor Tag CC2650STK