Update. On 18 May, the 3rd er9 RD died, and i contacted my reseller. 24 May, i contacted my reseller about my own er9 RD, because there are clear issues with recharging. Long story short, charging it, more often than not, results in the battery actually discharging. Go figure. I have a standalone lithium battery charger so i'm now using that until i get a replacement. I know a thing or 2 about lithium batteries, and i tried several different batteries (the actual Ltwoo battery compartment) as well as several different sets of lithium batteries, in various states of charge: the problem isn't coming the lithium batteries.
May 30th, still no resolution on either of them. my reseller makes it sound like ltwoo is being difficult this time around (for the previous 2, they were more straightforward).
The previous 2 broken ones (contacted my reseller on 17 Apr), i still havent received (it's not entirely ltwoo's fault, because they're in a box with a new wheel, so that took time too, but still, that box has been in transit for almost 20 days now, and i still have no idea where it is. So 1.5 months and still no replacement.
My friend whose RD died on May 18th had a triathlon the following weekend. He's back on his older sworks di2, at least the er9 died on a casual training ride and not on race day...
We're all loving Chinese groupsets in my cycling group, and the behaviour of ltwoo makes it extra tasty.