from a meaning of "average" to a meaning of "terrible"
It's a frustrating but predictable move.
I've always had a problem with how, when someone here in Yanqistan asks, "how're you doing?" you're supposed to answer "great!"* When I took French class and was told that the default expected answer was "ça va pas mal" (lit, "it goes not badly;" often truncated to "ça va" or "pas mal") and that it was exceptionally good answers (along with exceptionally bad ones) that would get you more probing questions, I was thrilled.
So... I blame America.
* I'm not noticing this so much anymore? But maybe people haven't been asking me how I've been doing as much, or it's a shift over the last decade with the rise of political polarization, or it's because I'm a little older now, or it's some combination of the aforementioned factors.