The newer cars have a totally different shift logic. My '15 Sport would downshift
while breaking, and it also resulted in higher RPMs than I would prefer, so I moved it
over to +/- when braking, and it didn't do that. Only when in "D" did it downshift
like that, I didn't like it, at all.
Now, I have a '12 SE 2.5, and I can leave it in "D" and it does not downshift like
that, like the '15 did, and what you're going through.