This is normal.
This is a forced-choice assessment. You can only select ONE statement as "Least Like You" and ONE statement that is "Most Like You".
You will see similar statements show up multiple times, but you'll notice that the set of statements is different. Where you might have said it was most like you previously, maybe the two statements that surround it now are more like you, which alters the priority a bit.
No one question alters your overall priorities much, but after 45 personality questions and 135 statements Plum gets a pretty good idea of your priorities.