Impact of mortgage transfers on credit scores

I have a very high credit score, but one thing I’m getting dinged a bit for is number of accounts opened in the last two years. This is mostly the result of multiple mortgage refis as the rates kept decreasing. However the number of “new accounts” includes 2 accounts for the same mortgage. I did a refi with Mortgager A, and after a month or so, they sold the servicing rights to Mortgager B. On my credit report, this counts and shows up as two separate mortgages, even though I did not apply for anything with Mortgager B and didn’t specifically want anything to do with them. This seems a bit weird to me.

I don’t intend to dispute the credit agencies over this, because 1) my credit score is pretty high as it is, 2) this has a very minor impact on credit scores, and 3) I don’t have any current intention to apply for any new credit in the near future anyway, and this should all roll off pretty soon. Not remotely worth the hassle. But I could imagine that it might impact people who are in a more borderline credit situation and are applying for things.

Questions are: Is this SOP or some error? What would be the logic behind it? And is this something that people can dispute, or that’s just the way it is?