I had this problem too. I bought my Tesla in September 2019. When I first entered it, the 7500 came up but it allowed me to key in $1875. Later, when I went back to file my taxes, it further reduced the 1875 by 25% and I didn't realize it until it was already submitted. I'm guessing the form was updated between when I first entered it and filed it. I'm waiting to see if the IRS accepts it or not, as that was the recommendation when I called Turbotax. I wish there was more help offered, since this was clearly a glitchy issue on their end.
