How on Earth are there already "more IETs▸ than usual needing repairs"? They're brand new for God's sake!
It doesn't
say that it's IETs needing repair. Could be an
HST▸ shortage, so they've taken an HST diagram off and spread a 10 car train over 2 x 5 car services.
Just thank goodness the train being split wasn't due to be formed of a whole load of 153s joined to each other!