light rattling noise between 20-40 mph. Sometimes you hear it at about 25 mph or 40mph

What is your question?

I thought maybe the catshield that was installed by Toyota might be loose or maybe something got loose when they installed it. Its a light rattling between the 25 mph then it goes away - Sometimes going up a hill between 48 mph you hear it slightly then goes away. Just had the 40K checkup and that seemed good.

What makes this problem better or worse?

N/A

How long has your 2015 Toyota Prius had this problem?

Few weeks