Movie artwork disappears on iPad Mini

Hello all, the title pretty much says it all. I had put a movie on my Mini. The movie was actually purchased from iTunes years back. I had it on there for nearly a week. I watched the movie, and throughout this time, the artwork was there. Anyways, I finished the movie, went back today, and the artwork is gone. It still played fine. Just want to see in case this happens again, what could be the cause or is this normal? I'll include pics of what it looked like because it also had a little blurry line under the movie title. Thanks in advance all.