Bevel cuts not lining up at the corners. After being cut by saw the two pieces lined up.
45"bevel cut. But upon installation on the house. They do not join correctly.
Do I need to shave off one board.25876

I think we worked on this last week too. Did you measure the buildings corner to see if it was a true 90 degrees? A closer picture would be better but it appears the board on the left is cut at 45 but not the one on the right, looks more like 60 degree. Put a bevel gauge on both and tell us what they read

You don't have to 45 that, just butt them up and don't worry about it. Who's going to look up and notice that.