Tweets repeating themselves over and over, NOT RT's!

I have set up a few catagories for certain people, like "Comedy" or "Animal Welfare/Rescue". When I was browsing the tweets in a catagory, the same section of tweets repeated themselves over and over. When I would scroll down, tweets would go back about 8 hours worth, then start again from 1 hour ago. Isn't that wierd? When I would scroll, instead of the tweets continuing at 9 hours ago, 10 hours ago, etc., the cycle of tweets from an 8 hour period would just repeat themselves over and over. Please fix this if you can!