I would laugh if the problems at the IRS weren't so pathetic. I feel your annoyance at your inconvenience and frustration.
Chances are that the great IRS computer behind the curtain spits out random correspondence letters from those of us who claim the credit on form 8936. The request for information is hard-coded into the nastygram (probably assisted by an IRS lawyer who knows the code and regulations.) Corroborating data like the IRS chart listing the 30D eligibility published on the IRS website is not part of the audit division. Ergo, the left hand does not know what the right hand is doing. Typical bureaucratic bovine excrement.
Then it is up to some low-level correspondence clerk to open up your reply and compare what you submitted to a checklist.
FYI--this is anecdotal, so don't testify to this in court--early filers typically get these sorts of things. This is all part of the statistical sampling of filed returns. If enough returns like yours are sampled with "no change" letters resulting, then the rest of us are spared this annoyance.
And remember, sooner, rather than later, Tesla will attain the 200K threshold. Then a lot of Model 3 buyers will begin to receive these notices, as I am sure there will be a ton of returns filed with the incorrect amount of credit claimed--either through ignorance or larceny.