AverageTable
First Post
I agree with you that the text -- "or challenge a different target" -- is confusing and shouldn't be there.
I also agree that this text is confusing and should probably have been phrased better; but it is, unfortunately, necessary for the rules to say something to this effect.
Without the "or challenge a different target" clause, it becomes impossible for a paladin to cease challenging one target and challenge a different one instead. Without this clause the rule would effectively read "On your turn you must engage the target that is currently challenged. Period." This would mean that once a target has been challenged, the paladin can do nothing but engage that same target turn after turn until it is dead (or abandon the target and suffer the consequences of not engaging). He would be unable to switch targets without an automatic penalty.
But yes, the rule should probably have been worded more clearly.