Characteristic 'On' expected boolean and received undefined.

[EnumC]

I'm observing the following stack trace while running version 1.3.3:

[26/10/2021, 03:15:05] [homebridge-switchmate-ble] This plugin generated a warning from the characteristic 'On': characteristic value expected boolean and received undefined. See https://git.io/JtMGR for more info.
[26/10/2021, 03:15:05] [homebridge-switchmate-ble] Error: 
    at On.Characteristic.characteristicWarning (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/Characteristic.ts:2074:105)
    at On.Characteristic.validateUserInput (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/Characteristic.ts:1951:14)
    at /usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/Characteristic.ts:1569:24
    at /usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/util/once.ts:9:18
    at /usr/lib/node_modules/homebridge-switchmate-ble/lib/OutletAccessory.js:224:13
    at processTicksAndRejections (internal/process/task_queues.js:77:11)
[26/10/2021, 03:15:06] [homebridge-switchmate-ble] Characteristic 'On': SET handler returned write response value, though the characteristic doesn't support write response. See https://git.io/JtMGR for more info.
[26/10/2021, 03:15:06] [homebridge-switchmate-ble] Error: 
    at On.Characteristic.characteristicWarning (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/Characteristic.ts:2074:105)
    at /usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/Characteristic.ts:1699:22
    at Object.callback (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/src/lib/util/once.ts:9:18)
    at /usr/lib/node_modules/homebridge-switchmate-ble/node_modules/async/dist/async.js:1529:26
    at /usr/lib/node_modules/homebridge-switchmate-ble/node_modules/async/dist/async.js:324:20
    at /usr/lib/node_modules/homebridge-switchmate-ble/lib/OutletAccessory.js:264:50
    at /usr/lib/node_modules/homebridge-switchmate-ble/node_modules/async/dist/async.js:4631:21
    at /usr/lib/node_modules/homebridge-switchmate-ble/lib/OutletAccessory.js:261:17
    at /usr/lib/node_modules/homebridge-switchmate-ble/node_modules/async/dist/async.js:3645:19
    at wrapper (/usr/lib/node_modules/homebridge-switchmate-ble/node_modules/async/dist/async.js:271:20)