Beats Flex microphone not working and LED always ON

My beats flex have two strange anomalies:

• The microphone does not work
  • The microphone of my iPhone has no issues, and I can hear audio through the earphones when connected. But even though I can hear the audio through the earphones, the microphone doesn't work. The only thing I can do is to turn off the earphones (and let the iPhone switch automatically to it's internal speaker and mic) or to select in the call options to use the internal speaker/mic instead of the bluetooth device.
• The LED of the power button is always on
  • So even when the earphones are powered OFF, the LED on the ON/OFF button is still turned on. Upon pressing the button (or when the earphone is scanning for BT devices) the intensity of the LED still varies but it seems as if the OFF state has been replaced with a "medium intensity ON state".

I tried performing a factory reset (holding power button and volume down button for 15 seconds) but this didn't resolve the issues.

Some of the details of my setup

Model number: A2295 (Beats flex)

Version: 3.7.2

iPhone: 15 Pro (MTUV3QN/A)

iOS 17.4.1 (21E236)