Having the same issue, I have one pair since July, ever since the December update the left bud has constantly low battery (hardly ever reaches above 75% and never above 90%) and discharges much quicker than the right bud.

(Keep in mind I’m the attached picture I placed the affected bud in the case 15 minutes as it was well below 25% and I needed at least one more hour of listening time)
Nothing should really fix this or at least put out a bulletin explaining the reason and what to do (replacement, repair, firmware update?)
I’ll request a replacement under warranty in the next few days even though it sucks to have to do that.
It is very disappointing to have such a promising product, with great functionality for an affordable price and then losing customer loyalty because you ignore the issues they’re facing. Absolutely stupid on Nothing’s part to behave like this.