This is not a bug. It is just bad labeling.

"Speakerphone" is the MICROPHONE at the bottom of the handset and "Headset earpiece" is the MICROPHONE at the top (near where your ear goes). These only exist on phones that can record in stereo natively but the bugs are:

• cannot select both, you need to setup 2 streams to record stereo by selecting each mic individually while on other devices you can record stereo from one stereo sound source relatively easily.
• cannot select output (maybe - as I have managed to set sinkId on some devices)