So, I have a part with a SurfaceGui and an ImageLabel. This is my "track". But then I added a "kart" which is a moving brick with a BillboardGui and also an ImageLabel. The issue is, sometimes the track goes over the kart making it invisible. It doesn't go fully invisible because to sort of prevent it the track is kind of invisible.
I finally realized! Thanks to my friend, I realized I just need to set AlwaysOnTop to true for the karts. If anyone else has this problem, now you know how to fix it hopefully.