Weird UITableView scrolling problem

I have a sectioned UITableView which loads data from a plist file. The table uses cu开发者_JAVA百科stom cells with dynamic height to fit the content of each cell. The table loads just fine initially, but after scrolling down and back up, the cells seem to be overlaying one another in some sections.

I've attached an image illustrating the issue I am having.

http://img20.imageshack.us/i/photo1b.png/

Any ideas on where to begin troubleshooting this problem?

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You need to set height for each cell in

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath