Are the ears suppose to stand all the time or just when they are alert? I have a 4 month old and when we take the tape off they lay to the side or back, but she can make them stand when she wants!!
The ears are controled my muscles and do not stand constantly. They stand when the dog is alert.
However, 4 months old might be a little young to expect them to stand.....depending on the style of crop, ear leather, etc....
If the appear to be flopping to the side, then I'm thinking that the puppy does not have good cartilage formed yet.
It is really something hard to tell without seeing the dog in person. Do you have any pictures of what they are looking like when erect, and in other positons? That might help some.