"CCCD Handle not found" error from characteristic.startNotifications()

I'm writing a port of the Bose AR Web SDK to Bangle.js. Right now I'm able to connect to the BLE device, get the service/characteristics and read/write values, but I get a CCCD Handle not found error when I run characteristic.startNotifications() on the characteristics with the notify property.

I looked it up and it seems to look for a handle_cccd property on the characteristic so I looked it up and found the cccd 0x1 and assigned it to the characteristics' characteristic.handle_cccd property, and the error stopped. However I still don't get any notifications when adding an eventListener via characteristic.on('characteristicvaluechanged', callback).