Just loaded the A350-1000 at Heathrow and experienced the same issue with Engine 1.
Engine 2 was fine and started normally. Outside Temp was 19 degrees.
I just did a flight from Krakow to Heathrow and noticed Terminal 5 wasn't visible, despite the jetways being there and passengers levitating.
It was there last time I used it a few weeks ago, prior to the last update I think.