Because of a shortage of 158s/introduction of 197s there have been a couple of round trips a day changed from going to Birmingham to instead being connections at Shrewsbury. It's possibly the case that this is one of them (and it was implemented by cancelling the original train and putting a new one in) - it does look about the right time to be the mid afternoon one. But obviously that doesn't affect you (other than positively as it might be a bit quieter for you).
Traditionally TfW just did this rather than putting it in the timetable if something without ETCS was going to end up on that diagram (because it doesn't affect journey time, just that you have to swap units at Shrewsbury, which they usually try to arrange as cross platform), but it is good that they have put it in the timetable so people can plan around it, though at the expense of a slightly confusing message for you.