KP97DC, That's exactly what they are supposed to do. If you look at the photo of the 8 round follower, you can see a little clip hanging down. That clip is what secures the magazine spring so the follower won't slide forward. Unfortunately, that little clip bends or breaks and the spring will allow the follower to slide forward.
If you compare the 7 round GI follower (which works fine in a Ruger magazine too) to the 8 round, you can see how much longer the leg is. That leg will catch the top coils of the spring and prevent the follower from going forward. With the Wilson follower, the enclosed body won't let the follower move forward.
I've been fighting these Shooting Star followers for well over 20 years and have replaced a ton of them. With Colt's bad track record, I can't believe Ruger went with the exact same model.