It refuses to update if it'll cost you over 100k in fees. Try an average transaction size of 3$ and a total monthly volume of 1,000,000$ for example.
If you're going to provide a slider with only a few pre-set values you should at least support all its combinations.
If you're going to make a mini-app and don't want to support certain values just don't make them possible rather than have buggy/wrong behavior.
If at least both refused to update it would be a little better than now where one of the prices can update with the other staying the same and thereby throwing the comparison completely out of whack.