Concrete Breakout Failure and Boundary Conditions

While modeling with the same loads and concrete edge conditions, in one model the right boundary where the concrete would be continuous and extends and the second where the concrete would only extend 12" from the anchor result in different results. In model one where the concrete edge on the right side extends, there would be concrete breakout failure. However, in the model two where the concrete edge is 12" from the anchor would result in a 72% unity for concrete breakout.