Been having the left earbud issue with mine as well. 5 tap approach didn't work, might need to warranty them. When you did that would both earbuds say they're in pairing mode? Or would the audio cue only come from the right earbud? Not sure if it could be related, but I also notice on the right earbud led will flash for a minute or so then power off when outside the case. The left earbud just continues to flash indefinitely.
Try tapping them 5 times while in the holder. That worked for me.