I have a 2018 M3 LR AWD that seems to have higher than normal degradation that hasn't flattened out as most seem to. Below is a teslamate chart showing my last 1 year where I've from from 288 miles of range at 34,230 miles down to 266 miles of range at 50,978 miles. The last time I took a screenshot from scan my tesla, it showed my "Full pack when new" was 77.8 kWh and my current "Nominal full pack" was 65.5 kWh. If my math is right, that calculates up to ~16% deg strictly from a kWh perspective. I do not believe I have any cell imbalance as scan my tesla normally reports only 4-6mv of imbalance between the max and min cell voltages. I have been very "nice" to the battery charging less than 10% of my total charge at superchargers and leaving my max charge set at 80% for most of its life. I always have the car plugged in when home, and store it in a garage in Georgia, so nothing to extreme from a temperature perspective.
My car also falls into a manufacturing date range (August 2018) where there are more than 1 TSB that could apply for range affecting battery manufacturing issues. I've asked Tesla service off hand if there is any way to find out if my car is affected by the manufacturing defects since its manufacture date falls squarely within the TSB, but they said no. Not sure what the purpose of the TSB is if there is no way to check for it and no action would be taken anyway unless you hit the normal battery warranty threshold anyway.
If my calculations are correct (admittedly I'm doing straight line math from 0 - 50k miles) at 120k miles my deg would be 103miles/~33% from a mileage perspective or 36% from a kWh perspective. From what I can tell looking at teslaloggers degredation graphs and comparing to what I read online, my deg is a fair amount higher than the fleet average. Does anyone have any suggestions for working with Tesla to investigate further whether my car is affected by one of the TSBs from the August 2018 manufacture date or am I stuck with the continued range loss until I hopefully finally qualify for warranty? I'd really hate to continue to plod along dealing with continued reduction in range waiting for that point and get to 120k miles with only have 29% deg or something silly like that.
View attachment 663413
Seems like your result is probably due mostly to luck (that seems to be the typical reason; there's really not a clear correlation). In any case your result is not extremely bad - it's not the worst that has been reported, especially given your mileage.
It will probably continue to slow down, and I really doubt you'll hit 30% before the mileage limit of the warranty.
My recollection is that Tesla reached out to owners actually affected by the TSB at the time, but I'm not 100% sure about that.
If you actually had blown fusible links in your pack (I think the subject of the TSB as I recall), I'd expect you'd see potentially large balance problems after a discharge (since not all the bricks would have the same number of connected cells, and so would change voltage at different rates, since the current draw from all the series-connected bricks is the same).