I have noticed that whenever I look at the revision history of a User Story, a new entry is added for that US. The same is true for Defects, Features etc... I don't change anything, merely look. Clicking back and forth between e.g. the description tab and the revision tab will create multiple entries in revision history. The entries are usually of the kind :
DESCRIPTION added [
This is not only annoying, it also makes it much more difficult to find the actual valid changes.