Greetings from Sunny Melbourne Australia where I am working outside and enjoying the autumn sunshine 23 degrees. :-) As a peace offering @Whatamidoing (WMF)please share some of my mandarin and green tea (t is very refreshing either hot or with ice)
On the en article The Trranformers: The Move I changed [within a paragraph and added a carriage return before. The diiff shows the whole paragraph deleted and re-inserted with one word the same (I have a screen dump)
Thank you for the fruit and tea. :-)
I'm sorry you ran into this. This happens sometimes, and it's a difficult mathematical problem to solve. There's a minimum amount, so if you change a single letter or a single word, it will show a larger amount as being "changed". (The alternative is highlighting single characters, and if you've ever tried to track down a change involving a single space in the pale blue/light yellow color scheme, you'll understand why they made that choice.) Additionally, it doesn't always make the choice around blank lines that a human would. So when you combine the two, it can cause "obviously wrong" results.
I generally find that some diffs are best handled by the wikitext system and others by the visual system. If one of them isn't working, it's worth seeing whether the other is better.