Ears don't often go up at exactly the same time.
I used to breed Cairns & often they'd be one ear up & one down for weeks, but they all went up eventually.
Teething can have a big effect, sending the ears up & down, till things settle.
It is a good idea to trim all the long hair off the top half, less weight to hinder them standing. Just take care with a wriggly pup
