Hard down shift after atf flush

Brought my car into the shop to have a few maintenance work done (atf
flush, acc drive belt replace, pcv valve replace, spark plug replace and coils
replaced)
driving it off the lot, I got up to 60km/h and then started to brake for a light,
the car dropped a gear either to late or too early either way it was noticable
shift in weight. My tranny was slipping a gear when downshifting. I assume
3rd gear to second.

I was told the car needed a relearn, and that i should drive it and it would
fix itself. nope. its been three weeks now, going to bring it back into the
shop now, any suggestions would be awesome? I cant tell if its getting
better or im getting use to it, but if i slammed on my brakes at 60 im scared
how hard the shift would be, trying to brake slowly but even then it will still
have a slight hard downshift. trying to coast into a downshift rather than
forcing a down shift I dont know,
im thinking a solenoid may need replacing or computer needs to be
reprogrammed but i was told the computer doesnt need work it needs time,
I dont like that answer :(