hi,i just meet the same question.i found it that the file you export may be named 20251105-211147 but the sav file was named POKEMON B.sav originally. So whatever the file is named after you edit your Pokemon,it may be named 20251106-211148(whatever)but the sav file must be POKEMON B.sav(the same as the original).
so as i did this,it worked.
wish it can help you.