There have been other electric cars with capacity loss like this.
There are several possible issues. Getting the dealer to troubleshoot this correctly might be the biggest issue.
What you can do to diagnose the problem:
Run the car as close to empty as is reasonable. Plug into a charging station that records the energy delivered. Some public charge stations do this, as you are billed by the kWh. Other public charging stations will report it as well. Take the number of kWh the car takes for the charge, and multiply it by 0.9 and you have about how much energy the battery received. Multiply by the inverse of fraction of the battery that was charged. If you discharged to 10%, then the total capacity of the battery would be Delivered_kWh*0.9/0.9, which is about delivered_kWh.
With a fairly accurate estimate of the battery capacity, now go talk to the dealer again. The range estimate or GOM (Guess-O-Meter) isn't good evidence, as it depends very much on how you drive. A recharge test is good evidence. Sure, the charging loss isn't exactly 10%, probably a few percent more or less. The battery isn't at 25C, probably colder, so the capacity would be a few percent higher if measured at 25C. But you are likely not more than 10% off, if done carefully. While the If the loss is enough to trigger the capacity loss warranty, or less than about 36 kWh, then the dealer should do a warranty replacement or repair. Based on you not able to drive 150 miles, I suspect that this is the case.
if the capacity isn't below 36 kWh, it sounds like it will be there soon. The dealer could do still do a "cell balance voltage" test, especially at a charge level below 20%, and might spot a very weak cell.
I suspect you have a single very weak cell. The dealer should replace that cell, or the whole pack. Other possible issues include a Battery Management System (BMS) fault.
