Multiplying issues so finally a call to tech support
Purchased my sleepbuds in January '19. Up to about a week ago they were fine.
The first problem was the drain on the right bud seemed to be twice as fast as the left: from 100% charge at night time the right bud was at half charge compared to the left in the morning. So I went through the firmware 2.0.0 update & case reset, "forgetting" on bluetooth & reinstalling...all solutions previously posted here.
So 2 nights ago I noticed that the charge on the right bud, after a full day's charge was...48%: and left was at 100%. Sound familiar? This is turning into a really consistent problem. I just could not get the right bud above 48%. Either the charge is going to 100% and then discharging back to 48% or not getting to 100% in the first place. Not that it matters, the unit is clearly faulty.
After that I didn't muck about: I called tech support in Australia this morning. After explaining the situation it was pretty clear the only solution was return of the buds & case for replacement. Received the paperwork & return label to do that 5 minutes later so will be mailing the current set back to Bose today.
It looks like Bose knows there seems to be a consistent fault and it seems they are reacting accordingly. Here's hoping the replacement unit is of a latest production run where the problem is solved.