Possible to get duplicate camera entries on Linux

From a testing report on the JavaCV changes, running on Linux with a single webcam attached/installed:

The device list showed me two copies of my webcam. If I selected either one of them, things worked great. If I tried clicked "close camera" and then changed to the other camera, things still worked great. But if I selected the other camera while the first camera was still in the "playing" state, I would get this error:

org.bytedeco.javacv.FrameGrabber$Exception: read() Error: Could not read frame in start().
 at org.bytedeco.javacv.OpenCVFrameGrabber.start(OpenCVFrameGrabber.java:265)
 at org.nlogo.extensions.vid.Camera.$anonfun$grabber$1(Camera.scala:71)
 at org.nlogo.extensions.vid.Camera$.withContextClassLoader(Camera.scala:31)
 at org.nlogo.extensions.vid.Camera.<init>(Camera.scala:69)
 at org.nlogo.extensions.vid.Camera$.open(Camera.scala:62)
 at org.nlogo.extensions.vid.CameraSelect.$anonfun$perform$1(CameraSelect.scala:13)
 at org.nlogo.extensions.vid.CameraSelect.$anonfun$perform$1$adapted(CameraSelect.scala:12)
 at scala.Option.foreach(Option.scala:407)
 at org.nlogo.extensions.vid.CameraSelect.perform(CameraSelect.scala:12)

Start by reproducing the report on Linux with one webcam, then inspect Camera.scala and CameraSelect.scala around the grabber creation and camera-selection flow. Use the OpenCVFrameGrabber.start() stack trace as the failure point. Done means one physical webcam appears once and switching cameras while another is playing no longer produces the reported read() error.