Is this a mistake?
Not all all. Whilst it’s quite common for the points where your tickets are split to coincide with the places you’re changing train, this won’t necessarily always be the case and if the two don’t correspond, it’s no cause for concern. Provided you follow the itinerary shown on your email confirmation you will not encounter any problems with the tickets you have been issued as the site will only offer splits at points where your chosen trains are timetabled to stop.
Are all the changes on my itinerary really necessary?
On certain occasions, due to limitations in the planning system we use we will suggest an itinerary that seems to includes extra changes that seem completely unnecessary. If you have a fixed time advance ticket for that leg, you must follow the specified itinerary along with with the changes it details. If you are using a flexible ticket, however, you may ignore extra changes if the time restrictions shown on the confirmation and during the booking process allow it.