Stick up cam lets out loud beep

I have 9 rings cameras and at least 3 of them have started beeping/producing tones, seemingly at random.
All the models with issues appear to be the Stick Up Battery Gen.2 model.
All cameras are plugged into power sources (some intermittent).
Cameras at different sites with different wi-fi of varying RSSI.

Here’s what I have observed:

  • Started a little over a week ago.
  • Tones may/may not be random, possibly related to motion but isn’t always triggered on motion.
  • Infrared LEDs turn off and on when the tone stops.
  • Tones last for 3 seconds exactly, possibly 2 seconds as well.
  • Tones consist of a combined 2kHz and 4kHz sine.
  • Also occasionally emits the same tone in very short bursts (<100ms).

My guess is the camera is signalling a fault or a state but I don’t believe this is documented behaviour.
Possibly some code left in the firmware during testing?
Was there a recent firmware update?

Settings of an affected device:
Firmware: Up to date (AUST Region) as of posting
Motion Freq: Frequent
Motion Sens: One notch below Max
Motion Zones: All 3
Motion Verification: Off
Motion Schedule: Off
Linked Devices: None
People Only: Off
Record Motion: On
Live View: On
Tap Live View: On
Rec Length: 120s
Snapshot Capt: 180s
App Notifications: Silent
Notification Pref: Push
Audio Streaming: On
Privacy Zones: Off
Partners Linked: None

Install Location: Indoors and Outdoors (2 affected devices)
Motion Notifications: On and Off (2 affected devices)